This was driving me nuts; on my Dell XPS8960 Desktop (Windows 11 x64), Realtek ASIO audio drivers show as clearly installed in Device Manager and "present" in File Manager, but never showed up as being available to select in any of my 3 music players. A reinstall of the latest Realtek audio package from Dell still wouldn't fix the problem. My older Dell XPS8930 (Windows 10 x64) always showed the ASIO drivers as available in MusicBee, etc.
Finally a helpful chap in another forum asked if the ASIO drivers had been registered, and sent a reg file to do it. Frankly I had always assumed the Dell install package naturally took care of that (as it had on the XPS8930). So I executed the reg and VOILA!, the ASIO drivers showed up as output choices in all 3 players! Man--Dell, who sends driver install packages that don't register themselves??
So if any of you are having the same experience with Realtek ASIO drivers not showing, try this registration file:
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\ASIO\Realtek ASIO]
"CLSID"="{A80362FF-CE76-4DD9-874A-704C57BF0D6A}"
"Description"="Realtek ASIO"
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\CLSID\{A80362FF-CE76-4DD9-874A-704C57BF0D6A}\InprocServer32]
@="c:\\windows\\system32\\rthdasio64.dll"
"ThreadingModel"="Apartment"
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\ASIO\Realtek ASIO]
"CLSID"="{A80362FF-CE76-4DD9-874A-704C57BF0D6A}"
"Description"="Realtek ASIO"
[HKEY_LOCAL_MACHINE\SOFTWARE\Classes\WOW6432Node\CLSID\{A80362FF-CE76-4DD9-874A-704C57BF0D6A}\InprocServer32]
@="c:\\windows\\SysWow64\\rthdasio.dll"
"ThreadingModel"="Apartment"
Their own control panel now useable:
(https://i.imgur.com/wNClZBH.png)