Deadlift Variations for a Sensitive Back

It helps that being injured has forced me to perform every crazy lift in existence.

That sounds like something you should see a sports medicine doctor/PT about if it persists.

For lifting during the mean time, Iā€™d suggest dropping all heavy deadlifting variations, and start working from a range and weight that you can manage with great technique/no discomfort. Stretch your hip flexors/roll your quads/stretch your hamstrings/roll your glutes. Start working on your upper back strength with pull ups/seated rows/seal rows, start doing heavy ab work (as you can do completely pain/discomfort free), and start working on your back extension. It sounds like something is fucked with your form, and it is probably because certain muscles are too weak to do their job stabilizing your spine, you are too immobile to do the lift, or your form just needs work (probably a mixture of the three).

Are you pulling the slack out of the bar before you try to break it off the floor? Are you bracing your spine correctly? Does your lower back round at any point during the lift? Are you arching too hard (I had that issue when I was less experienced)? Post a deadlift video, everything is just a shot in the dark until we see what is going on with the lift.