Not just your instance. Every instance Federated with it that got a copy of your post is part of the chain of evidence. Don't plan crimes in the fediverse for heaven sakes.
Given that the Fediverse is wide open, unencrypted, and your instance owner is no more immune to getting a subpoena from law enforcement than anyone else ... one might think twice about asking questions of the form "if I commit a crime can they find me" here. Even if your VPS can't detect it, you just left a paper trail here by asking how to commit a crime. :) Bad plan.
Your Fediverse instance owner might consider deleting your post and perhaps your account to keep them from being the subject of such a subpoena in the future.
And can instead move to a platform that is controlled by a rando instance owner with their own set of quirks and foibles. And can choose amongst thousands of such instances, each controlled by a different rando with a different set of quirks and foibles. Out of the frying pan and into the fire indeed.
Good.