I too have encountered excessive temperatures and crashes on my new M4 Pro Mac mini. I previously had bought (and later returned) an M4 (not Pro) mini and did not encounter this problem. The M4 Pro is a more powerful, and hence hotter, chip than the M4. I believe the 'problem' in games at least is due to this feature:
Use Game Mode on Mac - Apple Support (CA)
Game Mode pushes your mini past it's normal limits when gaming to get better performance. However the M4 Pro Mac mini's cooling doesn't seem adequate to handle the increased thermal load from Game Mode. Some informal testing in Baldur's Gate 3 with Game Mode disabled showed that the CPU temps were in the mid 80s and GPU temps in the low 90s. (On the Celsius scale that is.) Not great, but not enough to cause crashing. I do need to do more testing, but wanted to share preliminary results.
The downside of course is lower frame rates. But BG3 isn't a shooter, so high frame rates aren't necessary, not for me anyway. The alternative is to use fan control software, which does seem to keep the device cool enough. The fan noise might bother some, but headphones are always an option.
The Apple Support article above has instructions on how to disable Game Mode if any of you wish to try.
