The fediverse is inherently a place where it’s a lot harder to delete anything than on non-federated platforms. It always will be because everything you post here is instantly copied to hundreds (if not thousands) of other servers. Some of them may be actively hostile and intentionally not respect deletions. Some of them may just be misconfigured or for another non-malicious reason fail to delete things.

So don’t post things on the fediverse that you think you might one day regret.