If you want more people to join the fediverse, you have to improve the user experience. People don’t want to read an article breaking down what the fediverse is, how to join an instance, how to find content, etc.
Streamline the join process so it doesn’t require learning the lore and technical training. Stop promoting the fediverse generally, and instead push people to easy to use frontends and popular instances. Remove the barriers to entry. If they want to dig deeper into different instances and the technical stuff, let them do that later. Stop loading the info dump at the front.