@Tihiy
I was using StartAllBack on a Surface device (tablet) and noticed the mouse buttons option does not appear on the taskbar.
See attached photo for StartAllBack example and Microsoft website for how it should look...
https://support.microsoft.com/en-au/windows/open-the-on-screen-touchpad-2d402c64-949b-05ca-ebeb-978a6548d151#ID0EBD=Windows_11
This was on latest version (v3.8.13).