(not a tech expert, but I’ve been following it for a while, so I hope this is mostly correct)
Bluesky the app is currently the only (major) app running on the ATProtocol. The protocol itself is open source, and it is technically possible to run your own “federated” version (it’s not called that in the ATProto ecosystem, but that’s the rough equivalent in activitypub-speak). The protocol is still being developed, so it’s not as feature-complete as some people are hoping for, but it’s getting there.
https://www.techdirt.com/2024/10/29/some-slightly-biased-thoughts-on-the-state-of-decentralized-social-media/ for a more professional write-up on the differences, similarities, and criticisms of the major twitter alternatives.
One’s “own best interest” can take a lot of different forms. Especially when the number and variety of plausible candidates are finite. Your preferred candidate for a given office will rarely line up perfectly with your own values. There’s a compromise there.
If I vote for my own finances, it may come at the cost of my morals. It I vote for my own moral interest, it may cost me more. If I vote for my own power, it may cost someone else their freedoms. How heavily do I weight my own interests against those of a wider society? Political identities and philosophies are complicated, and can’t necessarily be reduced to a single binary choice that is “best” in every scenario.