When will Android 11 be available for the emulators? The R version is currently marked as 10.0+.

Just checked my setup, and mine are marked as 11 (I use Emulator 30.1.3 Canary) , you should also check which API's you have donwnloaded in AS. I use AS4.2C10, my latest APIs are Android 11 (R), API Level 30, Revision 3; Android 10 (Q), API Level 29, Revision 5; Android 9 (Pie), API Level 28, Revision 6.

I am using Android Studio 4.0 stable, so I guess that's the difference