@vkareh thanks for your improvements on this! I can confirm that Alt+Tab is now working reliably again.
However, other apps are still affected. Example, Firefox:
Normally, you can use Alt+1 or Alt+2 to switch to the corresponding tab.
I still need to press Alt+1+1 (pressing 1 twice) to trigger the action.
I think this should be working by just pressing 1 once.
Can you confirm this problem?