The left and right button (plus scroll wheel these days) are standardized and pretty much guaranteed to work on arbitrary USB mice because otherwise users would

The left and right button (plus scroll wheel these days) are standardized and pretty much guaranteed to work on arbitrary USB mice because otherwise users would revolt. Even reliable support for the middle button was a matter of luck for a long time, years ago (that was before scroll wheels were a thing). Everything else the OS can't really expect to work. There's a reason why vendors of such advanced input devices provide their own config tools for Windows and macOS: both systems don't even try to support that clusterfuck out of the box.