I have a laptop with limited decoding capabilities with regards to royalty free formats, which YouTube tends to use, but I do prefer the quality that I get out of av1/vp9 encoded content on YouTube when using those on my home PC over what I get through h264ify.
What I do have, is a server which runs Jellyfin and can transcode content just fine. Is there any software I could host which could transcode videos I watch with a browser extension via my server?
Sorry if this is jumbled or unclear but it’s something that I would really have a use for, and if feasible, would even write myself.
If you have a fast network you could transcode to high-bitrate h264/h265 etc, which would have some quality loss but probably less than using h264 directly (due to Youtube’s aggressive compression).
But I’m not aware of anything that ties it altogether either, especially if the OP needs browser support.