The biggest problem I see:
On your first two sets, your entire posterior chain is closed. This is a good thing. This means you are stable and you can transfer force through the floor, through your hips, and through your back. Your ligther sets were done with very good form, even though they were slow (x2 on the grip work).
Your 365 felt shitty and heavy because you tried to pull it with an open posterior chain. Something is going to give in when you pull with an open chain. Same goes for squatting and benching too. In this case, your lower back is in flexion before you even pull and your hips are almost over your shoulders.
Anyway, get your lower back locked in from the start, while you are standing up. With a tight back, hinge your hips to get into pulling position. This will help make the pull feel not so much like you are going to shit your spine out. Other than that, solid pulling, man.
x3 on the grip work.