The core issue here is instances disappearing, and That goes into the discussion of the structure of the fediverse right now vs. the fediverse in the future

A dozen big instances feel better now, and I personally wouldn't make a community on a smaller instance unless I know it is likely to stay up. If it was run by an existing organization for example.

Long term though, I trust existing organizations to set up stable instances that won't be shut down easily. If a government, school, game company etc. makes an instance it's not likely to go down. Having lots of instances will look more normal then.

Ultimately we don't need to do anything differently, I recommend new people join a big instance and then make a new account once they know what instance they like.

note to everyone: please don't downvote good faith questions

OP asked a pretty reasonable open ended question. There are other people who may be thinking the same, and reading the discussions here might change their minds. Save downvoting for rule breaking / content that's bad for the community