Why is the Speaker Fill Option Not in the Realtek Drivers for Windows 11, it's a rather simple APO feature that would take a developer a few hours to patch.

See this, it has the Enhancement Tab.

See this, the developer had too many beers and forgot to unhide the Enhancement Tab.

If your Sonic Studio 3 has upmix/surround and if you are correct that they are just different GUI pointing to the same functionality, then why would you even care whether your Realtek Audio Console has "speaker fill" or not. Just click the item in SS3.

Wrong SS3 is only a GUI all the buttons and switches link directly to the same driver functionality across all 3 GUIs. How do I know this, because I tested it with SS3 Open and the Realtek Audio Console Open and the Actual Windows Driver GUI Open clicking a feature in any of the 3 GUIs changes the settings in the other GUIs all use the same drivers it's only the GUI or the way it is presented that is different. I did email Realtek to see what they have to say about it.

Bottom Line: I don't care who fixes it, it just needs to be fixed.

My god man I'm 50 years old and have been building PCs since the late 90s I'm pretty sure I know difference between full range speakers and mid range speakers. Also, do you not see the distance adjustments in the picture i posted. Of course I tested them that would just be stupid to not exhaust all other possibilities first. This happened twice before with Realtek drivers once when we went to Windows 8 next time was when we went to Windows 10 and now with Windows 11.

If features are missing in the realtek audio console, it is because it got moved to another app (like sonic studio 3, nahimic, dts, dolby...).

For example, if they give you two 10 band EQ (i.e. the 1st 10 band EQ in the Realtek Audio Console app and a 2nd 10 band EQ in the dolby app), 100% of the general population will accidentally enable both EQ at some time --- thus ruining their sound. So the only technical solution is to delete the 10 band EQ in the realtek audio console app.