

I think it’s reasonable to keep content for 30 days, like holding it in a trash in case you want to restore it.
Other than that delete after 30 days thing, I was under the impression that deleting your account removed content permanently.
I seem to recall servers crashing here, there, and everywhere in the 0.18 (or maybe it was 0.17) days when a user with a lot of content deleted their account (which I presume was fixed).
Vote privacy can be tricky in an environment where every vote gets sent to thousands of instances and needs to be verified as legit via the ActivityPub protocol.
Piefed does a good job of this I think. If vote privacy is enabled, they create a second account that is used only for votes. Other instances see the votes and can validate them against the vote account but it’s not tied to the actual user (except in their home server database).
A benefit of this is that the vote account for the user is always the same, so you can still track vote manipulation, and ban the vote account if needed.