@HashbrownRolo You're right, and I said that Microsoft allows steering wheels to have some additional functionalities like an accelerator, brakes, clutch, and (as you stated correctly) wheel turn and shifting.
But regarding the maximum number of digital buttons, you are limited to the standard button catalog and cannot use an arbitrary button ID like on the PC. Just compare the XBox-compatible Logitech G923 with the PS4/5 version, and you will notice that it has fewer buttons AND resembles the standard controller.
Edit: Out of interest, what do plus and minus appear as in the F1 23 controller mapping menu?