I’m sure it’s possible, maybe ask on support?

Simply block it.

There is!

Click Communities, and from there you can sort Local (Communities that originate from your instance, for you it’s lemmy.world!), or All, which includes most communities every public instance (like how I’m commenting to you from beehaw.org!)

From there, simply subscribe to what communities you like, even if they come from a different instance.

Here’s a link for you to investigate.

I predict Reddit backing out, lowering the API price to something realistic, and then everyone forgets what happened, like every other time something like this has happened.