Is BlueSky similar to the Fediverse? No.
The Fediverse is owned by the people and communities that use it. A basic server costs $5 a month all inclusive, anyone can make one. It's ad-free, made by volunteers, funded by donations, servers are independent.
BlueSky is a for-profit corporation funded by VC money. Its technical structure makes servers dependent on expensive corporate-run relays. BlueSky's business setup is eerily reminiscent of Ello: https://waxy.org/2024/01/the-quiet-death-of-ellos-big-dreams/