This is false. The latter is, anyway. I am running 11 IoT LTSC on my main gaming rig and WMR is still supported. The key is, you cannot install a version any newer than 23H2. There are third party tools available that will block Windows from attempting to "upgrade" you to a new feature release which breaks WMR. My Reverb G2 is still working fine.

...For now. WMR support on a fresh install is still reliant on a Windows Store download which Microsoft will probably cease providing at some point if they haven't already.