With a torrent, you download a file or use a magnet link that then tells your client what file you want and it searches whatever index for people whose client say they have the file or the parts of it you don’t have. You are a leeching the data until your file is complete. You then can continue to seed the file as long as you have the torrent and the completed data.

Usenet is all text based and there are size limits to how big a file can be. You have a NZB file that tells your client the files needed and it works in a similar way but you don’t also seed the file back. It’s more complicated than that, but that’s my elementary understanding. I prefer Usenet. There are subscriptions to access the indexer and and Usenet servers, but I feel it’s worth the reduced risk if you’re sailing the high seas.

Get the arr stack setup (radar, sonar, et al) and you’ve got your own Netflix like management of Usenet media.

To your point of wanting to preserve and share your own media, if it’s not copyrighted use Torrents. I don’t actually know how you would host on Usenet as I’m just a consumer of the above.