There’s no such thing as “running a domain” or “atproto provider” in atproto. You’re approaching it with a Mastodon/AP mindset and it doesn’t match that.

In atproto, there’s two axes.

One is hosting. Bluesky offers hosting but some people host on their own (it’s just a Docker container with sqlite), some on Cloudflare, some on community-hosted nodes like https://npmx.dev and https://selfhosted.social. From app perspective it looks exactly the same way (unlike in Mastodon where “hosting” = “choosing a community”) and you can switch hosting anytime.

Another axis is apps. Apps aggregate from data from all hosts. Bluesky is an app, Tangled is an app, Leaflet is an app, Wisp is an app, Semble is an app, and so on. Those can all aggregate over the same data (which enables cross-app interop) but they don’t have to (eg Bluesky doesn’t overlap with Tangled much except that Tangled can reuse Bluesky avatar on login). Generally you don’t have people running copies of the same app (as in Mastodon) which is why there aren’t many “blueskyes”. But when someone has an incentive, they can. (Eg Blacksky is a complete fork including server and DB, allowing their own moderation decisions over same data.) Similarly you can build your own app on top of distributed Tangled data.

Hope that helps clarify why “atproto provider” as a concept doesn’t make sense. You have hosting, which is as distributed as you want, and you have apps, which anyone can make.

How does a new server discover other servers?