I believe there’s even scripts to repost them all from the archive to nostr.

Burning bridges! Make sure you change your birthdate to yesterday

You can download your archives. I forget exactly where but it's in your account privacy settings or something somewhere. You can request all of your content.

See https://exit.pub/

You might consider - before leaving Twitter - communicating there your departure to nostr. Through Tweets, a space or DM? Might get some other good folks over here. 😉