Both Dolby Atmos and V4A don't work at all on my RN7 with Xiaomi.eu 20.1.21, even with selinux set to permissive.
Edit: tried it on latest Pixel Experience rom + Magisk 20.3 and it works now
If anyone else's OCD is flaring up by looking at the *ucked up status bar, you can fix it in the developer options -> Simulate a display with a cutout -> Corner/Tall display cutout for full screen mode.