Hi @ShadowStar_Games and @anonymous_user_537a337d,
I had a lot to do with the early 4.19.3 UWP and trying to get things working.
The XBOX GDK etc can be found at microsoft/GDK: Microsoft Public GDK (github.com)
Beware this is only for The Xbox Series X and you need to have an ID@xbox.com account, which means you have an agreed game.
The UE5 does support the code look for the conditional compilation code XSX
Performance of the original Universal Windows Programming code, now re-badged as Windows Runtime which was from the days of Windows7/8 et all from the Xbox 360 generation. Performance🤣, you were lucky if it ran, it needed Microsoft library 1.138 then upgraded, because of VS2017 to MSRT140 I think, even UE 4.24 heavily patched does not seem to work anymore, with the latest windows 10. Good luck converting VS2015 runtime code, because after 327 hours I could not!!.