ok i see, you are having the pillsbury problem, basically your legs are locking out before the bar is even off the ground, thus eliminating all your leg power and making it a really dangerous and heavy sld
the good news is that if you pull 455 with that dogshit form you have the strength to pull 555 with proper leg drive....there are many fixes to this problem....if i were you I would start strengthening the bottom of the deadlift, that is what you are struggling with, and do more weighted core work....
to hit the bottom try speed deads, deads from blocks (the bar is lower), one hand deads, stiff arm pulls (basically a deadlift and a power shrug put together where you pull under conrtol and then explode from the knee)
the good news is that if you pull 455 with that dogshit form you have the strength to pull 555 with proper leg drive....there are many fixes to this problem....if i were you I would start strengthening the bottom of the deadlift, that is what you are struggling with, and do more weighted core work....
to hit the bottom try speed deads, deads from blocks (the bar is lower), one hand deads, stiff arm pulls (basically a deadlift and a power shrug put together where you pull under conrtol and then explode from the knee)