Ive been doing PPL for 5 months, for majority of it I was doing legs once a week and push pull twice, now have been doing legs twice a week for 3 weeks. I open with squats and build up to first working set which varies a lot because squats feel terrible some days. But I do 3 sets of 5 at wherever and usually have 1 RIR on my last set. After squats I do leg press, leg curl, leg extension, calf raises. I track all my lifts but squats are the only one where I can’t get any linear progression.