It's me again.
I've resolved the issue, leaving this here to anybody who might experience the same issue.
The autosave feature was having issues naming files, causing them to simply not be found by the game, the issue was resolved by deleting the vast majority of my save files (around 100)
and it resolved the issue.
A bit weird considering it happened to quick saving only, but now it works perfectly.
Props to the Mikohime, this conversion kit gave me a 2,5x performance uplift, especially good for 24x speed up.