You should check out some programs based on multiple sets of low but powerful reps. Stuff like CAT, or programs based around using 60-70%.
I can’t link to other sites, but if you search for “Sam Byrd CAT Squat” you should find an article about former world record holder Sam Byrd training with 60% for 5 x 5 and getting big results.
Reed who posted here trained with Byrd. In this thread he talks about CAT squatting with front squats for " heavy" work. Post #21.
Post #2768 in this log lays out a nice 16 week deadlift cycle from Mark using similar percentages.
Tasty Nate talks about his pretty slick system starting at post #21 in here.