Don't know if this is helpful, however:
when you click on set up keyboard layouts and you see the list of all the languages, select ONE layout (if you select more than one layout, it will stay with the previous layout), then, tap the arrow in the top left corner.
Xiaomi 10T MIUI global 12.5.3
physical keyboard 1byone with touchpad
With this trick I was able to switch from the german QWERTZ layout to an italian QWERTY layout, however, the special letters does not match. For example, if you press "è" it gives you "[" which should be given by pressing AltGr+"è".
Anyone knows how to fix? please not a manual remap of each key, all the special character to the side of the keyboard have this issue.
I tested the same keyboard with my samsung tablet S6 Lite (same app microsoft swiftkey and same layout italian) and it worked perfectly fine! All the letters are typed correctly even with shift and AltGr. So this should be on Xiaomi side.