Related: it’s been sad to see the HP48 emulators bitrotting. m48 is no longer available on the App Store, and I can’t find anything that works anymore for the Mac.
https://sourceforge.net/projects/emu48mac/
Kinda Mac-related is i48 for iOS:
https://apps.apple.com/us/app/i48/id329454950
hpcalc.org has a list of emulators:
https://www.hpcalc.org/hp48/pc/emulators/
Best seems to be Emu48, as mentioned above:
https://hp.giesselink.com/emu48.htm
x48 is open source, like Emu48: