If you're wondering how many hours of Marvel's Snap you can play on your phone per day before it melts your cpu and kills your device, it's two.
Two hours per day.

You're welcome.

@jestdotty surely there's something a mobile can do? Like pop up a warning if things are getting too hot whilst playing a game?

To be fair, my mobile is nearly 5 years old so I probably needed an upgrade, but to go out like that, before I could transfer things over, and with all of my 2-factor authentication and my banking apps etc is a pain in the arse.