I came across this thread, as MIDI input now also fails on my machine using Xkey Air/Widibud. Might it be, that this issue is related to installing KB5074105, which introduces new MIDI features?
[Windows MIDI Services] New! This update improves MIDI on Windows with enhanced support for MIDI 1.0 and MIDI 2.0, including full WinMM and WinRT MIDI 1.0 support with built-in translation, shared MIDI ports across apps, custom port names, loopback and app-to-app MIDI, plus performance improvements and bug fixes—delivering a better experience for musicians.