This topic can be closed and marked as solved.
The issue was with the hard drive. 3 drives suddenly started to give SMART errors. One is super slow (1mbps) even in another PC, one I can't fix with seatools, and the other one I'm running seatools long fix to see if I can still use it.
Never buying Seagate again. All 3 drives were from different batches, from Seagate (the parity as well).