Use LASIM to download your subbed communities next time lemmy.world is up. Make a new account on another instance. Upload your communities to the new account with LASIM.
Unfortunately, posts/comments don’t go - but you can do like me and just leave a trail between your accounts (if you care enough). I just link to and from my old/new accounts in the bio each time I make one. It’s a little janky, but it works - and it’s better than waiting hours for lemmy.world to be up for 12 minutes before going down again.