Does anyone have anything that works for MAX 2020? I have tried at least a dozen and none work.
You mean something like PSD Manager?
No, I have that and it works. The updated one for MAX 2020 is a little flaky and sometimes misses layers, so I need to quickly mask things. I found one that worked (Illusion Box Studios). It said for MAX 2019, but I was able to pick the MAX root.
I had a quick look at that tool, Rendermask, and it seems great. Free as well.