Do not simply search "RetroArch" on the Play Store and hit install. That version is often months behind. Here is the verified installation path:
The Google Play Store version for Android TV is notoriously buggy regarding audio sync. You need the 64-bit APK from buildbot.libretro.com. android tv retroarch verified
Most CRT shaders will kill performance on Android TV. Verified light shaders: Do not simply search "RetroArch" on the Play