How to debug

Run the command to check plank related info.
journalctl --user -xe | grep plank

Seeing bamf related msg

bus-daemon[1547]: [session uid=1000 pid=1547] Activating via systemd: service name='org.ayatana.bamf' unit='bamfdaemon.service' requested by ':1.85' (uid=1000 pid=2405 comm="plank" label="unconfined") dbus-daemon[1547]: [session uid=1000 pid=1547] Activating via systemd: service name='org.ayatana.bamf' unit='bamfdaemon.service' requested by ':1.751' (uid=1000 pid=7270 comm="plank" label="unconfined")

Then check bamf status
systemctl --user status bamfdaemon.service

Seeing it failed to start

× bamfdaemon.service - BAMF Application Matcher Framework
Loaded: loaded (/usr/lib/systemd/user/bamfdaemon.service; static)
Active: failed (Result: exit-code) since Wed 2025-03-19 18:03:55 +08; 5s ago
Duration: 2min 16.290s
Process: 403834 ExecStart=/usr/lib/x86_64-linux-gnu/bamf/bamfdaemon (code=exited, status=1/FAIL>
Main PID: 403834 (code=exited, status=1/FAILURE)
CPU: 8ms

Mar 19 18:03:55 systemd[1509]: bamfdaemon.service: Scheduled restart job, restart counter is >
Mar 19 18:03:55 systemd[1509]: bamfdaemon.service: Start request repeated too quickly.
Mar 19 18:03:55 systemd[1509]: bamfdaemon.service: Failed with result 'exit-code'.
Mar 19 18:03:55 systemd[1509]: Failed to start bamfdaemon.service - BAMF Application Matcher >
Mar 19 18:03:58 systemd[1509]: bamfdaemon.service: Start request repeated too quickly.
Mar 19 18:03:58 systemd[1509]: bamfdaemon.service: Failed with result 'exit-code'.
Mar 19 18:03:58 systemd[1509]: Failed to start bamfdaemon.service - BAMF Application Matcher

Solution

So we know it failed to start due to request repeated too quickly. Therefore we need to delay bamf startup.
To do that:
mkdir -p ~/.config/systemd/user
cp /usr/lib/systemd/user/bamfdaemon.service ~/.config/systemd/user/
nano ~/.config/systemd/user/bamfdaemon.service

Find the [Service] section and add this line:
ExecStartPre=/bin/sleep 2