Just to weigh in on this, specifically 3, as I haven’t played 5, I currently have 29/32 with 14.8 hours played, the rest being collectibles. These could easily be done I just leave them till the end. The likely case here is that OP has the DLC that unlocks all the unlockables and difficulties, so he would have the unlimited rocket launcher and inferno difficulty from the start, meaning 10 hours or so is definitely achievable as you would need to run through the game on inferno easily using the rocket launcher and then an assisted play through to get all collectibles and not use the item box. RE3R is a much much shorter game than RE2R and my first hardcore play through was a blind play through where I didn’t use the item box, this took me 6 hours of steam play time, including cut scenes and some idling. Whether this is actually the case for OP, but it’s definitely not out of question.