When I was in yiur situation. I just did the McGill Big 3, lots of walking, and focus on perfect spine hygiene.
Then I started doing goblet squats (I tried to make them look like low bar squats, deep hinge, a#@ back) to a high box. Over time I was squatting most parallel, to a box, pain free. Then I replaced the 24kg bell with an empty barbell. After a while, I removed the box. After a while I started adding 10 lb to the bar, basic linear progression.
I would avoid ballistics for a while. Focus on Grinds. But I'm no doctor nor am I a trainer.
Eric