You have several options for the software you chose to use and even the user interface design but just remember that they can all communicate with each other because they all use the activityPub protocol. We know it can be a bit confusing to understand but just think of them like email applications that can all send and receive messages to each other.

• Mastodon - Free and open-source software for running self-hosted social networking services. It has microblogging features similar to the Twitter service, which are offered by a large number of independently run Mastodon nodes (known as "instances"), each with its own code of conduct, terms of service, privacy options, and moderation policies.
• Pleroma - Microblogging server software that can federate (= exchange messages with) other servers that support ActivityPub. Pleroma will federate with all servers that implement ActivityPub, like Friendica, GNU Social, Hubzilla, Mastodon, Misskey, Peertube, and Pixelfed. Pleroma is written in Elixir and uses PostgresSQL for data storage.
• Misskey - Decentralized microblogging platform using ActivityPub protocol and developed with NodeJS and PostgresSQL. It has the most features of all the other similar applications but may not be suitable for very large instances.
• GORF-AP - A fork of Misskey fully translated into English with ongoing improvements in performance and styles.
• PeerTube - Decentralized alternative to video streaming platforms such as YouTube using activityPub Protocol.
• PixelFed - Decentralized alternative to Instagram using activityPub Protocol.
• Lemmy - Decentralized alternative to Reddit using activityPub protocol.
• Lenny - Fork of Lemmy that respects users by not trying to control their speech.

• The Federation