The solutions would likely be different for different types of content. Let's take video as an example, because YouTube is such a pervasive platform.

Bittorrent works well for video transport, but by itself doesn't solve adaptive streaming during consumption or compression and format conversions on upload.  Peertube currently solves those problems, and can be used until there is nostr-native server software (already integrates webtorrent even). For bitcoiners, there is e.g. the https://bitcointv.com instance.

Instead of rewriting all kinds of solutions, I think it would also be feasible to simply add optional Nostr integration to all kinds of software, like e.g. Peertube, so that instance admins who care about that could just flip a switch and allow all their users to publish to Nostr in addition to RSS and ActivityPub for example.