you seem to have added the buster repos here instead of the bullseye ones. Try using the no subscription one listed under “Proxmox VE 7.x” in the wiki in your "/etc/apt/sources.list.d/pve-install-repo.list" instead.
Also note that PVE 7 is out of date, so you may want to upgrade to Proxmox 8.x soon.
This just means that the service in question couldn't start fast enough. journalctl -xeu pve-ha-crm.service should provide you with more information, please post the output of that command.