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.
Your rx5700 going over 100°C ? That's crazy mate, how do you sleep conveniently in the night? Just because it's working doesn't mean it's safe, a gpu running at that temp can cut lose all it's memory chip and you will start getting memory size error, don't do it 😔