Temperature doesn't mater, been mining since 2017 at very high temps. No issues. GPU has temp sensors, that's what they are there for. If it overheats, software will take care of it. If it thermal throttles, its too hot.

I see people installing delta fans, and other expensive cooling on their rigs. I just don't get it. Why waste money/power?

I have some rx5700 with 106deg memory temperature, been running flawlessly for over a year.