Since you say you did nothing to it, could be the BIOS battery is dead and BIOS options got reset.
How old is your ThinkPad? What model? What version of Mint? (Mint is based on Ubuntu, AFAIK)
People having this problem seem to have wrong UEFI BIOS settings. Seems not only ThinkPads are affected.
https://askubuntu.com/questions/1404141/ubuntu-22-04-reset-system-bootloop https://old.reddit.com/r/Ubuntu/comments/ssy57h/reset_system_then_restart_after_installing_ubuntu/ https://askubuntu.com/questions/1373339/ubuntu-20-04-stuck-in-reset-system-loop
(post is archived)