@hellomiakoda I can try to vomit some ideas but best over sync chat, I am not used to doing tech support over fedi haha
Specifically, I would try to look into any kinda logs, Pam usually would log stuff somewhere
And I would check the config files
Lastly, making a backup of /etc/passwd & /etc/shadow and wiping them, with a recovery USB ready + several root shells opened to be sure, could be a nuclear sanity check
It might also be one of the Pam modules failing. Maybe there is one that checks the status of the power daemon... Maybe try to reset the status, unsure.