Assetto Corsa in Odyssey+ unavoidably involves Windows Mixed Reality Portal and SteamVR,
which support only controllers that I find intolerable
and make no sense when sim driving. Without a controller,
using 2-D apps such as Content Manager in HMD is seemingly impossible,
except perhaps with a virtual desktop app.
G29 rim buttons become unavailable when using AccuForce.
If more than a couple of controller buttons are needed, a flight joystick may be wanted.
In Steam > Settings (SteamVR must be turned off) > Controller, General controller settings.
Uncheck all but Xbox Configuration Support
and Xbox Extended Feature Support.
Open SteamVR; a gamepad icon should appear. If not, be sure to open SteamVR by clicking VR button in Steam.
Make applicable mappings from virtual gamepad in SteamVR app.
TIPS:
If HOTAS Throttle doesn’t work or is mapped upside down,
clear the input and map it to W and S keys with a joystick profiler.
Make sure no keys are pressed while launching the game.
Windows Mixed Reality added Win32 app native support
with Windows 10 Version 1903.
I do not know how they get launched:
"Access the feature by bringing up Pins Panel via the windows button on your controller,
then go to all apps, where you will find a folder named 'Classic Apps'.
In this folder, you will be able to select and launch any Desktop (Win32) applications."
Run Desktop (Win32) apps in WMR