I use my Sculpt with Windows, but I've tried using it on a Mac Mini m1, and it was horrible due to the lack of drivers. Maybe that plays a part in terms of the wonkiness as well.
Did you try switching your keyboard preference from Apple to PC Layout in keyboard preferences?
I did not try on M1, but this keyboard works pretty well with a MacBookPro early 2015 (and it was for a French Azerty Sculpt keyboard, not even the regular US Qwerty!).
Pro tip: on a Mac laptop, add a key shortcut to switch between the 2 layouts, so that you can quickly switch from one to the other layout.
Also add the keyboard icon / input source in the menu bar, for quick visual check : it shows the actual keyboard layout.