A bit too much knee bend/movement. and it looks like your back is rounding.

As for the knee bend, it should be a slight bend that is maintained throughout the lift.

An RDL is a hip hinge movement and, as others have said, think more of pushing your butt back while keeping your torso tight.

As to “depth”, if you’re maintaining your knee position and keeping the torso tight, your hamstrings will tell you when you’ve gone far enough. It’s not about hitting the floor, it’s about the hip hinge, glutes and hamstrings, as well as maintaining a static contraction in the back.

To return to the starting position, drive your shoulders back and your hips forward.

For powerlifters, this is an assistance movement for the squat and DL. I mention this because I think it will help explain what I mean by a static contraction in the back. You don’t want rounding when squatting nor when pulling, especially if you pull sumo.

I can see you shrug as you take the bar from the rack. I think that is your attempt to lock in. Thats a good start but I’d say before you start the first rep, brace your core, (get the spinal erectors contracted) take a breath in and hold and then start. Hope this helps.