No no no no no, please y’all remove the term OpenComposite from your vocabulary. Your game IS NOT using OpenComposite, MSFS is a native OpenXR game, it has NO WAY of using OpenComposite. And just the idea of trying to use OpenComposite with a native OpenXR game is completely absurd.
What happened is that you switched your system to use WMR instead of SteamVR as your OpenXR runtime. This is why SteamVR exits. This is 100% unrelated and different from OpenComposite.
Simple fix to switch it back to SteamVR: