Box squatting was a temporary fix for my patellar tendinitis for a while but it eventually came back when the weight got heavy. I was doing three sets of five at 435 when I stopped due to having a hard time getting out of bed or driving because my knees hurt so bad. From there I tried only deadlifting and wasted a bunch of time because my deadlift went to shit from not squatting and my legs got weak too. I went to a ssc and drilled the hell out of the low bar squat and have been good since. So I’d try to find a ssc around you and learn the proper lift and maybe wrap your knees if they are that bad. Also from my own experience my box squat didn’t translate to low bar much at all. I tried doing 225 low bar while box squatting in the 400s and was blown away at how hard it was. .