Yeah what the other person said - the Tdarr instance was for my other media and I figured, might as well use it across the board. It was less work to just add another library to Tdarr and let the server go brrrr than to work out how to get ytdl-sub to do that, especially when the library was already in the hundreds of GB.
`--recode-video` is probably the better solution if starting from scratch.