Only force unlock a VM if you know it's stuck (i.e. Don't unlock a VM if a system process has it locked while said process if running. Wait until the process has finalized and the VM is froze in a locked state).
Open a shell on the PVE host that has the locked VM
qm unlock <vmid>pct unlock <cid>If, after all attempts, the service state could not be recovered, it gets placed in an error state. In this state, the service won’t get touched by the HA stack anymore. The only way out is disabling a service:
ha-manager set vm:100 --state disabled