I have tried 12 instances with most posts according to https://lemmyverse.net/?order=posts . I am able to find most post on 1-3 largest instances (those listed on the top of that page).

Is there any meta-search across many or all Lemmy instances? So i do not have to waste time opening many instances manually and doing search for each of the missing posts on each?

After updating the link and this link will become offline in the future, can i repeat the process or it wont work, because federated post can not be federated again (2nd level)?

Open big instances listed at https://lemmyverse.net/?order=posts and on its Search pages, search for a full post URL of the old/dead instance. I wish there is some meta search engine which would search many instances in one go.

Can anyone summarize leading post, i do not understand what it means. Clickbait title but WTF is clear and short explanation/message in basic english to the users?