Same here, ~9-10 seconds until it open.
Fresh install of ubuntu 24.04. Intel® Core™ i7-4770 × 8 / 24Go RAM / Xorg / Version: 24.2.3.2 (X86_64) 

LibreOffice Community
Build ID: 4f88f79086d18691a72ac668802d5bc5b5a88122
CPU threads: 8; OS: Linux 6.8; UI render: default; VCL: gtk3
Locale: fr-FR (fr_FR.UTF-8); UI: fr-FR
Calc: threaded


2024-05-06T21:52:05.841623+02:00 michael-desktop systemd[2145]: Started snap.libreoffice.calc-c1a2c0de-14e4-46a9-bdf0-ef7770807b05.scope.
2024-05-06T21:52:05.898108+02:00 michael-desktop systemd[1]: tmp-snap.rootfs_H1kMyU.mount: Deactivated successfully.
2024-05-06T21:52:12.041413+02:00 michael-desktop soffice.bin[3590]: Not loading module "atk-bridge": The functionality is provided by GTK natively. Please try to not load it.
2024-05-06T21:52:12.129876+02:00 michael-desktop soffice.bin[3590]: GTK+ module /snap/libreoffice/319/gnome-platform/usr/lib/gtk-2.0/modules/libcanberra-gtk-module.so cannot be loaded.#012GTK+ 2.x symbols detected. Using GTK+ 2.x and GTK+ 3 in the same process is not supported.
2024-05-06T21:52:12.130053+02:00 michael-desktop soffice.bin[3590]: Failed to load module "canberra-gtk-module"
2024-05-06T21:52:12.132528+02:00 michael-desktop soffice.bin[3590]: GTK+ module /snap/libreoffice/319/gnome-platform/usr/lib/gtk-2.0/modules/libcanberra-gtk-module.so cannot be loaded.#012GTK+ 2.x symbols detected. Using GTK+ 2.x and GTK+ 3 in the same process is not supported.
2024-05-06T21:52:12.132634+02:00 michael-desktop soffice.bin[3590]: Failed to load module "canberra-gtk-module"
2024-05-06T21:52:12.203428+02:00 michael-desktop dbus-daemon[2181]: apparmor="DENIED" operation="dbus_method_call"  bus="session" path="/org/gnome/SessionManager" interface="org.freedesktop.DBus.Properties" member="GetAll" mask="send" name=":1.37" pid=3590 label="snap.libreoffice.calc" peer_pid=2472 peer_label="unconfined"
2024-05-06T21:52:12.203532+02:00 michael-desktop dbus-daemon[2181]: apparmor="DENIED" operation="dbus_method_call"  bus="session" path="/org/gnome/SessionManager" interface="org.gnome.SessionManager" member="RegisterClient" mask="send" name=":1.37" pid=3590 label="snap.libreoffice.calc" peer_pid=2472 peer_label="unconfined"
2024-05-06T21:52:12.269085+02:00 michael-desktop dbus-daemon[2181]: apparmor="DENIED" operation="dbus_method_call"  bus="session" path="/org/libreoffice" interface="org.freedesktop.DBus.Properties" member="GetAll" name=":1.39" mask="receive" pid=3590 label="snap.libreoffice.calc" peer_pid=2515 peer_label="unconfined"
2024-05-06T21:52:12.397776+02:00 michael-desktop dbus-daemon[2181]: apparmor="DENIED" operation="dbus_method_call"  bus="session" path="/org/gnome/SessionManager" interface="org.freedesktop.DBus.Properties" member="GetAll" mask="send" name=":1.37" pid=3590 label="snap.libreoffice.calc" peer_pid=2472 peer_label="unconfined"
2024-05-06T21:52:12.398005+02:00 michael-desktop dbus-daemon[2181]: apparmor="DENIED" operation="dbus_method_call"  bus="session" path="/org/gnome/SessionManager" interface="org.gnome.SessionManager" member="RegisterClient" mask="send" name=":1.37" pid=3590 label="snap.libreoffice.calc" peer_pid=2472 peer_label="unconfined"
2024-05-06T21:52:12.897339+02:00 michael-desktop dbus-daemon[2181]: apparmor="DENIED" operation="dbus_method_call"  bus="session" path="/org/gnome/SessionManager" interface="org.freedesktop.DBus.Properties" member="GetAll" mask="send" name=":1.37" pid=3590 label="snap.libreoffice.calc" peer_pid=2472 peer_label="unconfined"
2024-05-06T21:52:12.897601+02:00 michael-desktop dbus-daemon[2181]: apparmor="DENIED" operation="dbus_method_call"  bus="session" path="/org/gnome/SessionManager" interface="org.gnome.SessionManager" member="RegisterClient" mask="send" name=":1.37" pid=3590 label="snap.libreoffice.calc" peer_pid=2472 peer_label="unconfined"
2024-05-06T21:52:13.036269+02:00 michael-desktop kernel: audit: type=1326 audit(1715025133.034:188): auid=1000 uid=1000 gid=1000 ses=3 subj=snap.libreoffice.calc pid=3590 comm="configmgrWriter" exe="/snap/libreoffice/319/lib/libreoffice/program/soffice.bin" sig=0 arch=c000003e syscall=92 compat=0 ip=0x7d9e78499a6b code=0x50000
2024-05-06T21:52:13.102815+02:00 michael-desktop dbus-daemon[2181]: apparmor="DENIED" operation="dbus_method_call"  bus="session" path="/org/libreoffice" interface="org.freedesktop.DBus.Properties" member="GetAll" name=":1.39" mask="receive" pid=3590 label="snap.libreoffice.calc" peer_pid=2515 peer_label="unconfined"
2024-05-06T21:52:13.522253+02:00 michael-desktop kernel: audit: type=1107 audit(1715025133.520:189): pid=1079 uid=101 auid=4294967295 ses=4294967295 subj=unconfined msg='apparmor="DENIED" operation="dbus_method_call"  bus="system" path="/" interface="org.freedesktop.DBus.Peer" member="Ping" mask="send" name="org.freedesktop.Avahi" pid=3590 label="snap.libreoffice.calc" peer_pid=1078 peer_label="unconfined"
2024-05-06T21:52:13.522263+02:00 michael-desktop kernel:  exe="/usr/bin/dbus-daemon" sauid=101 hostname=? addr=? terminal=?'
2024-05-06T21:52:14.447254+02:00 michael-desktop kernel: audit: type=1326 audit(1715025134.445:190): auid=1000 uid=1000 gid=1000 ses=3 subj=snap.libreoffice.calc pid=3590 comm="configmgrWriter" exe="/snap/libreoffice/319/lib/libreoffice/program/soffice.bin" sig=0 arch=c000003e syscall=92 compat=0 ip=0x7d9e78499a6b code=0x50000
2024-05-06T21:52:15.487260+02:00 michael-desktop kernel: audit: type=1326 audit(1715025135.485:191): auid=1000 uid=1000 gid=1000 ses=3 subj=snap.libreoffice.calc pid=3590 comm="configmgrWriter" exe="/snap/libreoffice/319/lib/libreoffice/program/soffice.bin" sig=0 arch=c000003e syscall=92 compat=0 ip=0x7d9e78499a6b code=0x50000
2024-05-06T21:52:19.429244+02:00 michael-desktop kernel: audit: type=1326 audit(1715025139.427:192): auid=1000 uid=1000 gid=1000 ses=3 subj=snap.libreoffice.calc pid=3590 comm="configmgrWriter" exe="/snap/libreoffice/319/lib/libreoffice/program/soffice.bin" sig=0 arch=c000003e syscall=92 compat=0 ip=0x7d9e78499a6b code=0x50000
2024-05-06T21:52:13.155606+02:00 michael-desktop dbus-daemon[2181]: apparmor="DENIED" operation="dbus_method_call"  bus="session" path="/org/libreoffice" interface="org.freedesktop.DBus.Properties" member="GetAll" name=":1.39" mask="receive" pid=3590 label="snap.libreoffice.calc" peer_pid=2515 peer_label="unconfined"
2024-05-06T21:52:19.930229+02:00 michael-desktop systemd[2145]: snap.libreoffice.calc-c1a2c0de-14e4-46a9-bdf0-ef7770807b05.scope: Consumed 9.356s CPU time.