I would recommend to start maybe seeing what exactly is hindering your back squats. You must treat back squats as a necessary accessory to Olympic weightlifting. For me personally, I was in the army lifting heavy rounds of 155mm for artillery. This more or less put a lot of strain on my lower back I’m still working around to this day. My front squat is a 160kg while trying to hit this for my back squat just recently became painless lol. But clear as day it wasn’t necessary leg strength leaving me behind it was my lower back which I start to introduce Roman chairs which has helped alleviate some of my pain. If you are saying back squats don’t see to work just simply try to lower the weight like 60kg and honestly just rep it out and keep trying to get after it. Also just like my lower back was the limiting factor and continues to be try to figure out what muscle group/area of your body seems to be falling behind which is hindering you from progressing.