when it happened to me a week or 2 ago I just kinda bit the bullet and went through the people who follow me, and then scoured global and already happening conversations. it's like 1 really annoying hour of clicking and opening and closing your app when it freezes.

I have seen someone post a few times about building a nostr backup tool. if I come across the post again ill try to tag you/repost.

I think if you log into nostrgram it has the recover option or something. I think its just a website.