This would work well. Instance owners could add a few "tags" for things their instance is doing. Then a user could have a wizard-like experience that you could say "what are some things you're interested in?" and then it could give them some recommendations on servers to join based on that. With some big verbage that says "But don't worry, you can access everything else on Lemmy through here" and maybe display the blocklist too underneath it so they know what that server actively blocks.