I'm not aware of a single modern mouse that doesn't use regular HID for actual basic mousing. All these mice will work as basic HID mice in any operating syste

I'm not aware of a single modern mouse that doesn't use regular HID for actual basic mousing. All these mice will work as basic HID mice in any operating system. If your legacy OS can't handle "5 mouse and 3 keyboard", its HID support was completely broken in the first place.