If you do want a fully federated Lemmy, note that LemmyWorld won’t do it. Since they have been defederated by Beehaw, you will not be able to see any new content from the large communities on Beehaw. If you want to see everything, you would have to choose a home instance that is not Beehaw or Lemmy.world or sh.itjust.works. If you join another instance that is still bidirectionally federated with all three of those, then you will be able to see content from all three.
If you do want a fully federated Lemmy, note that LemmyWorld won’t do it. Since they have been defederated by Beehaw, you will not be able to see any new content from the large communities on Beehaw. If you want to see everything, you would have to choose a home instance that is not Beehaw or Lemmy.world or sh.itjust.works. If you join another instance that is still bidirectionally federated with all three of those, then you will be able to see content from all three.