There was a button/CTA to join a recommended fed, this was second in the list. What if you go to the settings sidebar and click federations?

Try this invite code

fed11qgqzz8mhwden5te0vejkg6tdd9h8gepwvchxjmm5w4hxgunp9e3k7mf0qyqjpj2ykt73ullqfj58lxjh67y5ed53zm8vvfjvk5h65ufz3a8v2nxky9wuce