My experience with the anime and tokusatsu fansubbing community is the opposite. There's a lot of "you must use mpv or CCCP", and a ton of disdain for people who watch on something other than a PC.
A small handful of groups will provide alternate "toaster-friendly" downloads for people on set-top boxes. For example, for ongoing TV shows, the main release will be a 720p or 810p softsubbed MKV with Hi10P video, and the "toaster-friendly" release will be a 480p hardsubbed MP4 with 8-bit video. This is mostly in the tokusatsu scene, though; for set-top boxes, the anime community mostly relies on dedicated encoding groups like DeadFish who provide "toaster-friendly" versions of other groups' releases because most groups won't even consider releasing something that's set-top-box-friendly. Also, there is an assumption that if you don't want to watch on a PC, then you don't mind SD video.
For fansubs that use Blu-ray-sourced video, there are no "toaster-friendly" options. You can basically expect groups to do a 720p Hi10P release alongside a 1080p release which is either Hi10P or HEVC, both of which are softsubs-only and in MKV containers. The audio is often, but not always, FLAC.
For those unfamiliar with how subtitles work, softsubs are incompatible with pretty much every set-top box. And there are some groups that will use intricate typesetting that can bring even decent PCs to their knees. For example, Commie is notorious for releasing an episode of JoJo's Bizarre Adventures with typesetting so over the top that it crashed most people's computers (I've never seen the episode myself, but I understand it involved hundreds of lines of text all continuously zooming in and out).
But even the anime/toku community doesn't use AV1, and HEVC is only for 1080p releases sourced from Blu-ray video (and to reiterate, a lot of groups will still use Hi10P even for 1080p).