Lemmy.world is awesome but the servers are overloaded and things don’t load sometimes. Lemmy.ml is the next largest instance and seems to be a bit more stable but tradeoff is slightly less users. It depends on your personality too, if you are a super political activist you will probably want to join a political based instance matching roughly your alignment. If you’re a sports but there are sports instances. There are over 1000 Lemmy instances each with their own goals and community. Keep in mind not all instances automatically federate with all other instances, they have to cross interact manually by users once for two instances to ‘know’ about eachother. So the larger all purpose instances like world and ml will have a much more diverse ‘all’ feed. Also some instances are defederated by most of lemmyverse due to allowing hateful toxic user behavior and inappropriate content