it’s open source: github.com/…/activitypub-federation-queue-batcher

I strongly recommend fully understanding how it works, which failure scenarios there are and how to recover from them before deploying it in production though. not all of this is currently documented, a lot of it has just been in matrix discussions.

I also have a script to prefetch posts and comments from remote communities before they’d get through via federation, which would make them appear without votes at least, and slightly improve processing speed while they’re coming in through regular federation. this also doesn’t require any additional privileges or being in a position to intercept traffic. it is however also not enough to catch up and stay caught up.
this script is not open source currently. while it’s fairly simple and straightforward, i just didn’t bother cleaning it up for publishing, as it’s currently still partially integrated in an unrelated tool.
I previously tried offering to deploy this on matrix but one of my attempts to open a conversation was rejected and the other one never got accepted.