Comment 9 for bug 1951491

Ok, so the logs you attached earlier are:

2021/12/03 15:21:45.540312 tracking.go:45: DEBUG: creating transient scope snap.chromium.chromium
2021/12/03 15:21:45.543273 tracking.go:185: DEBUG: using session bus
2021/12/03 15:21:45.547127 tracking.go:290: DEBUG: StartTransientUnit failed with "org.freedesktop.DBus.Error.Spawn.ChildExited": [Process org.freedesktop.systemd1 exited with status 1]
2021/12/03 15:21:45.547174 cmd_run.go:1187: DEBUG: snapd cannot track the started application
2021/12/03 15:21:45.547199 cmd_run.go:1188: DEBUG: snap refreshes will not be postponed by this process

When snap starts the /usr/bin/snap binary tries to create a scope for the application. The scope is needed so that the app can run in a separate cgroup which is then confined to access specific devices. Unfortunately this is the only way to set this up on a cgroup v2 system. The setup is done by talking to your `systemd --user` instance. In the log it's clearly indicated that it failed and systemd exited, thus no scope and the app cannot be run, because the confinement would break your session cgroup (.slice/session-1.scope). I'm afraid I don't know enough about your setup to guess what could be wrong there and why the user instance may have exited. Perhaps reviewing the user logs (journalctl --user) could help uncover the problem.