It's not distributed, nor really designed at all like the fediverse. It is deeply centralized, and its architecture requires it to be centralized, or at least to have only huge players with a "gods eye view" for it to work.
Atproto was initially designed as a straight drop in replacement for twitter, so its design makes sense, but its not at all like the Fediverse.
One of the authorities of ActivityPub, the fediverse protocol, just did a very kind but still very blunt breakdown of Bluesky's design choices. she is a big fan of the people involved and some of its positives, but it is not fediverse like, not at all. In her words, it doesn't scale down, only up. You cant have a small bluesky server. To work, you need all data sent to everyone, on every instance. The data demands for just the current influx is TBs/month of data, and climbing (according to the link below, they use 16TB of nvme storage right now after the recent surge, which would be thousands /month on any cloud service. This will climb dramatically).
All data being public is a design choice by Bluesky. It is also a different design choice by the fediverse that comes to the same outcome, but that does have an answer if we want it. I know gotosocial did something interesting to make fully private votes by using a empty shell profile that votes, but tying that in a tricky way to your account. So there are fediverse answers to privacy, but there may not be bluesky answers.
EDIT: One of the blueksy/atproto devs replied to the above link today. The gist reinforces the point that the service is intended to be run by large orgs, including corporations, but also big non profits like the internet archive or Wikipedia. His take is that user experience is key, and for that you need big money and easy features. They are hoping that since the pieces of atproto can be hosted separately by separate giant orgs, that market forces will make it viable to be decentralized.
Im not an expert either, but both people in the above links are. They are both worth reading if you want to understand the platforms better.
As to blueskys user data portability, it's part of the protocol to a degree, but it's not a reality. The design is such that only megacorps/giant orgs can host the bluesky service. It doesnt really matter if your data is portable if no one will let you import it. Its akin to google reader and rss. People could export their rss feeds when google shut down google reader, but without an rss reader, it didn't matter. That data had no usable context.
These is a drastic asymmetry problem with bluesky. It demands a giant player to gatekeep, whereas the fediverse lets anyone, anywhere add or even begin a network.
The Fediverse doesnt have a parallel of data portability at all, so even that lackluster implementation is something, but to both protocols defense, the Fediverse is talking about changes to activelypub to add this, and bluesky is attempting to make small services more possible.
Still, in all reality, neither of these platforms offers anything like that today, or likely in the near future.