I'll ask the question why do you want something hosted, if you don't want the files to be on the server too, or at least accessible via a mount. There's a couple projects who do that for a reason, you can't just upload an 80gb video file through a web interface simply. For home use it makes more sense for it to be connected to some sort of nas and you point it to the file on the nas, and then point where on the nas you want the output file.
As written, I don't think you'll find a lot. I think what may serve you better is finding a server solution that watches a directory and then runs transcodes based on pre defined templates, and spits them back out in a known location.
The problem exists of how do you get files to the server. Again for a big video file you need a place to have the original accessible for the entire duration of the transcode, and you need a drop point to place the file when it's done. And if you're doing that, more than likely you have something like Plex or jellyfin, so why not just hook it up to your existing file locations?
I run jobs all the time from my cluster, but the issue always comes back to persistent storage. Where are the files you need to act on, and where should the finished results be placed? You're trying to skip those important steps here.