Solid bitrate? I used 400 kb/s AV1 constant bitrate for HD anime, 750 for HD realfilm, results in 300 MB and 500 MB files for 2 hours video, no artifacts. Why does Handbrake default to 6000 kb/s?
Yes. If you don't have hardware that supports AV1 decode, it gets sent to the CPU instead.
For homelab stuff, the responsibility falls on the server to transcode the media to whichever format the client device requests.
That usually means being able to have ~2 simultaneous AV1 streams and maxing out the CPU.