[Raspberry Pi Original Development] KonstaT:
Thanks for the extensive report but there isn't much that hasn't been discussed before (so I'll just copy-paste my previous replies).

I'm not supporting any multi-boot solutions. If you've followed some other installation method than what is described under 'How to install' you would need to report your issues where you've found the image/instructions. But yes, flashing e.g. OTA packages is expected to be broken if you've used PINN due to how the partition numbers are handled. You of course shouldn't be using some outdated build from last year when there's newer ones available! Always use the latest build.

Last I tested MindTheGapps doesn't replace the default launcher with the Google one (OpenGApps does). Google's Android TV launcher only displays app icons for Android TV applications and that's expected behavior. In any case GApps are not part of my releases and I don't have anything to do with any GApps release. If you have issues with GApps, you would need to report them where you got the GApps package.

Wouldn't the obvious solution be to use default 1080p resolution if using something else is causing you issues. :) I'm not sure what you would achieve in practice by using 4k resolution anyway. GPU on the Pi is not that powerful and this would only decrease graphics performance as there's four times more pixels to render. Software video decoders can't keep up with 4k videos, so what is the point? But yes, you can remove/comment out 'ro.sf.auto_lcd_density=true' and adjust value of 'ro.sf.lcd_density' property in /vendor/build.prop if you want test things out. I don't have any 4k displays I could use to test in any case.

Android TV is not intended to be used with a mouse or a touchscreen. You need to have a remote to navigate the system (USB remote, Bluetooth remote, IR remote, TV's remote using HDMI-CEC, arrow keys on your keyboard, etc). Mouse options in Raspberry Pi settings are there for the regular tablet UI builds and I just haven't hidden the options for Android TV as the functionality is still there.

Alsa loopback is used to support HDMI audio on builds with Linux kernel >= 5.10. For background as for why, see https://github.com/raspberrypi/linux/issues/4651 & https://github.com/raspberrypi/linux/issues/4654. There can be some distortion/cracking caused by loopback underruns when there is heavy CPU load. This only affects HDMI audio output - 3.5mm jack/DAC/bluetooth/USB audio is fine. If this is too much of an issue for you, you can use builds with <= 5.4 kernel (i.e. Android 11 or older).

Both Netflix and Amazon Prime are reported working. You need to sideload the regular mobile version of the apps, though. Android TV versions of various streaming services tend to have more restrictions (SafetyNet, etc) and Netflix on Android TV even has server side whitelist so this only works on certain official/certified Android TV devices (which Raspberry Pi is not of course as it's not even an Android device to begin with).

Hw video decoding option only applies to H.264 videos. It will have the exact same issues with any app that uses H.264 (many Android video streaming apps use e.g. VP9 these days so it has no effect there). See e.g. https://xdaforums.com/t/dev-rom-aosp-android-13-for-raspberry-pi-4-b.4481977/#post-87316981 for current status and more information.