To me, Mastodon's overwhelmingly the best model. Even Bluesky has already shown that it's too centralizable, and I think very few people have considered the idea that "you can take it with you" is actually a bug as much as it is a feature, it's like Bluesky has added on potential surveillance and less anonymity.
Decentralization sounds nice in theory but seems to be detrimental to this type of social media, though. I briefly tried mastodon, and it wasn't easily possible to explore content spread across various hosts, which made it uninteresring.
Yes, this is a structural vs. social thing. My gut is that though, it would be entirely possible to build "nice and easy to find" ON TOP OF, as opposed to fully integrated with, a decentralized service.
"Just be kind of like email" is better.