I have somewhat the same problem (snap-store/Ubuntu Software doesn't start) on a freshly upgraded Ubuntu 20.10 system, with snap-store version 3.36.0-82-g80486d0

Removing/reinstalling snap-store doesn't work for me.

Here's the output:

ml@ml-dell:~$ snap-store
Attention : le schéma « org.gnome.system.locale » comporte le chemin « /system/locale/ ». Les chemins commençant par « /apps/ », « /desktop/ » ou « /system/ » sont obsolètes.
Attention : le schéma « org.gnome.system.proxy » comporte le chemin « /system/proxy/ ». Les chemins commençant par « /apps/ », « /desktop/ » ou « /system/ » sont obsolètes.
Attention : le schéma « org.gnome.system.proxy.http » comporte le chemin « /system/proxy/http/ ». Les chemins commençant par « /apps/ », « /desktop/ » ou « /system/ » sont obsolètes.
Attention : le schéma « org.gnome.system.proxy.https » comporte le chemin « /system/proxy/https/ ». Les chemins commençant par « /apps/ », « /desktop/ » ou « /system/ » sont obsolètes.
Attention : le schéma « org.gnome.system.proxy.ftp » comporte le chemin « /system/proxy/ftp/ ». Les chemins commençant par « /apps/ », « /desktop/ » ou « /system/ » sont obsolètes.
Attention : le schéma « org.gnome.system.proxy.socks » comporte le chemin « /system/proxy/socks/ ». Les chemins commençant par « /apps/ », « /desktop/ » ou « /system/ » sont obsolètes.
13:53:34:0901 Gtk Failed to load module "canberra-gtk-module"
13:53:34:0918 Gtk Failed to load module "canberra-gtk-module"
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0669 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0670 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0671 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0671 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0671 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0671 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0671 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0671 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0672 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0672 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0672 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0672 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0672 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0672 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0672 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0672 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0672 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0672 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0672 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0672 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0672 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0672 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0672 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0672 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0672 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0672 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0672 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0672 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0672 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0672 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0672 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0672 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:40:0672 XbSilo xb_builder_node_unlink: assertion 'XB_IS_BUILDER_NODE (self)' failed
13:53:41:0268 Gs  plugin appstream took 5,3 seconds to do setup
13:53:41:0275 Gs  enabled plugins: desktop-categories, fwupd, os-release, packagekit, packagekit-local, packagekit-offline, packagekit-proxy, packagekit-refine-repos, packagekit-refresh, packagekit-upgrade, packagekit-url-to-app, appstream, desktop-menu-path, hardcoded-blacklist, hardcoded-popular, modalias, odrs, packagekit-refine, rewrite-resource, packagekit-history, provenance, snap, systemd-updates, generic-updates, provenance-license, icons, key-colors, key-colors-metadata
13:53:41:0275 Gs  disabled plugins: dpkg, dummy, fedora-langpacks, fedora-pkgdb-collections, repos
13:53:44:0280 Gs  /etc/PackageKit/Vendor.conf file not found
13:53:44:0994 Pango pango_font_get_hb_font: assertion 'PANGO_IS_FONT (font)' failed
Erreur de segmentation (core dumped)
ml@ml-dell:~$