I think that the problem is vendor related, because every custom ROM running Android 10 and Xiaomi vendor has this bug, Linage OS use a custom vendor on Android 10, Instagram works perfectly
Yes, tried on the two xiaomi.eu Miui 12 betas, Instagram don't work, volume bar bug when connected to chromecast still don't work eighter. Miui 11 running in Android 9 works pefectly both things