Is that running on Rosetta 2? Rosetta 2 does (or did, maybe it's removed now) a fine job running x86 code on Apple Silicon, but boy was it cycle-hungry to do it.

BG3 is a native game, they dropped x86 support shortly after launch on macOS (or maybe even in beta)

Apple Silicon is not really the simultaneously silent and quiet and cool system it was in the M1 days.

If you get a MacBook Air it will get quite toasty at throttling limits. After all, it has no fan.

MacBook Pro models and Apple computers in general tend to favor quiet operation over keeping the laptop surface cool.

Many PC gaming laptops go out of their way to keep warm air off the keyboard deck with a high willingness to use fan noise to accomplish that since the assumption is that you’re resting your hands on the computer for an extended period and you have headphones on for your game anyway.