I'm actually kind of at a loss to think of a successful Zuck the Fuck product.

Facebook wasn't his, that was the Winkelvoss twins and he just stole the idea and got to market first. Threads is just Mastodon with the serial numbers filed off and some surveillance code added, and is further only a success because everybody with a Facebook account had a Threads account, but it seems to be an also-ran in the "microblogging" realm.

WhatsApp he purchased. Instagram he purchased. Oculus/Quest he purchased. In general the successful Meta products outside of Facebook seem to all be purchased products. And when he "innovates" products (like the Metaverse, like his AI junk, like Libra, like Lasso, etc. etc. etc.) they tend to flop on their face, often before even being formally released.

I think Zuck the Fuck was a one-trick pony, and he stole that trick.