Might be a silly question, but: does ActivityPub support setting up a subinstance that gets its data from somewhere else? Traditionally you’d probably do that with a pgsql machine and multiple frontends, but having thought about it while typing this out, putting that load on the ActivityPub protocol would mean loading up the master to much the same extent as just having the traffic hit the master directly…
On my phone so I can’t dig out links, but there are two tools being recommended: Redact and PowerDeleteSuite. Both allow you to edit the comment/post before deleting, because if you straight-up delete the message Reddit reserves the right to the message content as it stood at deletion.