How can I delete a Facebook account without waiting 30 days?

I don’t think mere mortals can go around what https://facebook.com/help/224562897555674 says (30 day grace period, may take up to 90 days, copies may remain in other accounts)

Also, if the data is publicly available it probably is too late for that, and if any knowledge of the earlier existence of the account remains, its deletion alone is suspicious (likely less so than its content)

I would change the password to something really complex (generate a long random string), ask Facebook to delete the account, and destroy the password. Then, nobody can force you to undelete it in the grace period. Ideally, change the email address associated with the account, too.

If you have a safe way to store it, make a copy first (GDPR’s right to data portability helps here). If they have to flee, having one can help getting asylum.

If you disable the account all access too it will be cut immediately and whatever there was on that wall will be out of sight.

Not that I'm aware of (I work at FB, but not related to accounts).

Use it to spam content against the terms of use. Perhaps not immoral and very illegal, copyright protected things can perhaps be enough to trigger the Facebook ban hammer.

What about a GDPR request. The right to be forgotten. As I understand it, you have the right to get all your information removed.