I'm not aware of any, and any such platform that is comparably featured would be susceptible to the same problem. This isn't a platform problem, it's a law problem.

There's a few that are used, but Google's shrewd marketing combined with natural selection have done a very good job marking those as the "terrorists and crackpots" youtubes.

And like all self-fulfilling prophecies, those claims are now largely true.

Do you have Docker? Then you can use an open source web UI rather than run the command-line tool.

  cat > youtube-dl-webui.Dockerfile <<EOF
  FROM d0u9/youtube-dl-webui
  RUN pip3 install --upgrade youtube_dl
  EOF
  
  cat > conf.json <<EOCONF
  { "general": {"download_dir": "/tmp/ytdui/download","db_path": "/tmp/ytdui/webui.db","log_size": 10},
    "server": {"host": "0.0.0.0","port": 5000} }
  EOCONF
  
  docker build \
        -f youtube-dl-webui.Dockerfile \
        -t youtube-dl-webui:latest \
        .
  
  mkdir ytdui && chmod 777 ytdui
  docker run \
        --rm -it \
        --name youtube_dl_webui \
        -p 5000:5000 \
        -e FLASK_DEBUG=1 \
        -e CONF_FILE=/conf.json \
        -v `pwd`/conf.json:/conf.json \
        -v `pwd`/ytdui:/tmp/ytdui \
        youtube-dl-webui:latest
  
  firefox http://localhost:5000/

That's the simplest one to get running I think (https://github.com/d0u9/youtube-dl-webui). Another is in PHP (https://github.com/timendum/Youtube-dl-WebUI).

Peertube comes to mind for discoverability. For ensuring content creators revenue, the best way would probably be to host their own website and put videos behind paywall or accept donations, as they see fit.

Seems like a perfect area for patreon to expand into.

Support a user/artist on patreon, get access to their vids also hosted on patreon.

Indeed. Or even make sure to integrate Patreon (or other donation applications) to any privacy-friendly video application.

I have a Twitch account just to have a paid subscription for the Critical Role channel, despite the fact that I never open Twitch and download their videos from Youtube using youtube-dl. It kind of feels ridiculous (especially knowing Twitch will put me in metrics of "their users").

Patreon is going to face the same issue then.