I’d lean to leaving it open access.

Too many places become effectively ‘walled gardens’ and become difficult or impossible to just stumble across.

Of course, there are the cost and performance considerations. idk if there’s a way to monitor logged in vs others. Or is there some way to prioritize serving responses to logged in users? I guess lemmy may not have that capability, and I don’t know how the server/instances are setup, but maybe split to have one server serving logged in users, and another to cater for the rest?

Meh, it may be adding to complexity for little benefit.