That’s a fair point that I had not considered – it’s a shortcoming in the premise of my inquiry. I wonder if it’s possible, if at all, to create any recommendation service that doesn’t compromise on user privacy. It may not be, as it would require a user’s history, which, given enough entries, can be used to identify them.
Unfortunately, comments, and votes don’t appear to be federating from Peertube. I’ve opened some issues (LemmyNet/Lemmy#4314, LemmyNet/Lemmy#3837, LemmyNet/lemmy-ui#2161) for this in the past, and, from what I’ve heard, it may be an issue with Peertube’s federation implementation.