Mastodon is an effective Twitter alternative that supports decentralization via ActivityPub. It could use some visual enhancements, but given that it's open source and built on an open protocol — perhaps that will happen in 2023!
If you can take the time to build your follow graph, Mastodon provides the highest signal to nose ratio I’ve personally experienced in recent memory. The lack of recommendation algorithm defaults and the openness of the platform (allowing for a proliferation of clients) make Mastodon stand out from the exodus of Twitter DAU.