First time I've ever seen someone monetize a form check video.
When you're done reading this, please go here and purchase a belt --->
Shop | Dominion Strength Training
Your back is not tight and you could do with narrowing the grip to get a more solid interface between the back and bar. Before you unrack, walk the hands closer to the shoulders and lift the chest up so your upper back is tight and the bar is locked in. Then, before each rep, lift your chest up to set the back.
Get leaned over sooner and maintain control into the bottom so you're not getting loose and plopping in the hole.
Tough to tell with dark sweat pants, but most reps look ok.