I see this really good plan on t nation which, despite its... branding... seems like a solid layout for a plan [1]. It makes for a good read, but if you feel confident with it, the table with the percentages and the table with the example workout would be sufficient. The idea appears to be that it's a 4 week cycle on any given primary compound lift - the first week is the 5 reps, the second week is the 3 reps, the third week is the 5/3/1 so you can blast that 1RM. Then the fourth week is the deload since you're attempting to max out your central nervous system. I imagine if you're getting too much volume from 3x5 then you have issues beyond our scope (we can't do medical advice). I like this idea that, in the pursuit of getting bigger numbers, you're focusing in precisely on getting that progressive overload in by increasing intensity and decreasing reps. It's all based on your (calculated) 1RM and I'd probably just type in my working set into the exrx calculator and then put that number into a spreadsheet with the percentages from tnation [2]. There wouldn't be any guess work in what weight or how many reps you're doing on any given day, it might just take a couple cycles to dial in what your 1RM is so you can make the cycle be the appropriate amount of intense. Does this answer your questions? Does it seem like the move?

[1] https://t-nation.com/t/5-3-1-how-to-build-pure-strength/281694

[2] https://exrx.net/Calculators/OneRepMax