They were always something I avoided. I have a bad back, visibly curved on the x-rays with a turned in shoulder. When I started squats I did not not have the core stability to do the exercise correctly. Not lack of strength really, but a lack of coordination and nerve adaption, and exercising all the tiny little muscles for balancing a heavy dynamic load. (Rather than stabilized loads like you get with weight machines.)
My first attempt was the empty bar which is about 35 lb -- and I almost fell over. I couldn't get my knees horizontally parallel to my waist, either. My knees wouldn't flex that much, and neither would my ankle.
So I started with unloaded exercises, using a ballet bar to balance. Fast and slow stretches. Body weight squats. Worked up to doing 100 sets of them. My knee stopped feeling weird. I then went through a phase where I would sit down on the ground and then lift myself back up with small dumbbells, from two 10 lb weights, eventually working up to the 35 lb ones.
Then I attempted the unloaded bar again. Almost fell over again. Went back the next day. After a couple months the motion was confident. Slowly started loading it. Now at 3x3 at 135 lb. Some of the younger men at the gym eyeball me like "What?" -- but the scoliosis only shows on an X-ray and I'm too old to worry about what people at the gym think. I'm very proud of it and never thought my body could do this.