Compatibility of YouTube downloads

Out of the following choices, which one would be the best in terms of compatibility and quality with a Vero 4K+?

VP9 + AAC in mkv
VP9 + OPUS in webm
H264 + AAC in mp4
AV1 + AAC in mp4 (I know the Vero cannot HW decode AV1, so ignore this option)

Every audio track @ 128 kbit/s


Hadn’t heard of this audio format before, but apparently supported by Kodi:

In progress.

VP9 will give you best quality and lowest bitrate for now.

I kinda baffled by this satement, cause AFAIK OPUS is the codec used by Discord, WhatsApp etc. but maybe you just made a late April Fools’ joke.

I don’t use either of these services. It seems to be a replacement for Vorbis / Speex.