function keys

something is missing. i went and booted into my catalina boot drive to see if there was a difference between monterey (which i'm using) and catalina. the "keyboard" panel in SP on catalina is a little different than the one i posted above from monterey. but you are still missing the check box you need. here's what i mean.

so since you say you are using a magic keyboard, and you are using catalina (so intel processor) i would try and reset your mac's SMC and also the NVRAM.

How to reset the SMC of your Mac - Apple Support

How to reset NVRAM on an M1 or Intel Mac

Is this a 3rd party external keyboard? If Apple does not understand your keyboard, it may not be prepared to assume the function keys behave the way it expects.

You could try a 3rd party keyboard mapping utility. I use BetterTouchTool, but there are things like Karabiner and Keyboard Maestro etc... Most of them have a demo period so you can try before you buy (although I think Karabiner is free).

you're welcome. and, i think next i would try a "safe boot" and see if the missing option appears. if while in safe mode that option finally appears, then i would run in safe mode for ~10 minutes. then reboot normally and see if this issue has been resolved. sometimes a safe boot will fix issues.

my bad. i forgot to add this link incase you need it.

How to use safe mode on your Mac - Apple Support

you can go into SystemPreferences > Keyboard and ensure that "Use F1, F2 etc. as standard function keys" is unchecked.