Although, as a casual gamer, I'd like to be able to run the games that I bought in the Apple App Store on my Mac. (e.g. "DeathSpank", a fun spoof of action RPGs, is 32-bit, so it's now unplayable.)

I've used crossover to play Skyrim on my M1 mac (and they just sent me an email saying Apple leveraged crossover code for their porting toolkit), so there might have been an option prior to this - if the performance is good enough for your game.

If you do want crossover, get a free trial, but wait for a discount. I think they discount around 30-40% near the end of the trial and during special sales.