Maybe only allowing OC
May happen if we have copyright problems, but somebody else singing a song is usually fine considering the amount of covers on YouTube.
What about the platform to host the media
Another user suggested PeerTube. I will build a simple web page with submissions from each year put together in a nice way via embedded PeerTube players.
We could backup the videos to several instances, offer archival downloads, but the internet will probably do its thing and back it up thousands of times as soon as we upload anyways.