How are users that aren’t interested in following the state of each community supposed to know which one is “on top” or the best community

The same way they have been doing it on reddit. You browse around, see a community that looks interesting and you subscribe. Notice that you have two related communities and you merge them in your client.

I don’t agree that making meta-level knowledge of the site mandatory to successfully navigating it is healthy or smart for the long term success of lemmy.

I mean, you need to know how a service works in order to use it effectively. Lemmy works a certain way and that’s that.

Not sure which you’re arguing for – that Lemmy should be simpler (I think it’s fairly simple for what it is) or that clients should be simpler (which is happening as we speak) – but either way it’s going to work out. Hell, Twitter’s mechanics are a lot less intuitive and it still managed to make it big.