Be patient as you create your new Mastodon account. There are many different servers to choose from. If you have the means and feel adventurous start an instance all your own with some friends! I have one and I host it for $6US/month at Masto.host. They have amazing service, my site is always up, and upgraded to the latest versions of Mastodon so I don’t have to worry about a thing. They also scale up so you can have a small group, like I do, or you can have thousands of users.
Big or small it all works together to form a single community with different interests and viewpoints. It’s like the internet was intended to work! A bunch of different sites all talking to each other to form a collective. There is no central authority, like you have with Twitter.