Re Bluesky I did some "I am not a lawyer" digging.

Bluesky is owned by "Bluesky Social PBC", a Public Benefit Company registered in Delaware.

Generally speaking it means when decisions about the company are made, they must take into account how that decision benefits their stated public value. I struggled to find the specific value wording, but let's assume it's a reasonable one for the time being.

Unfortunately being a PBC is basically voluntary, especially when you're still a private company. You can become a non-PBC with a simple board vote. (A public company would require a stockholder vote.)

Bluesky's board consists of four members, one of which is Bain Capital, aka the company funding Bluesky.

So Bluesky is absolutely a better alternative to Twitter. If everyone left Twitter and moved to Bluesky that would be a monumental improvement.

However Bluesky is not a non-profit company, as the above graphic states.