https://feedland.com/?username=robalexdev is the closest variant I know. You can see who else subscribes to feeds that you follow, and see what other feeds they like. The current version doesn't have a recommendation engine, but you could easily build your own.
> so I'm never showing up without something new.
I like a feed I can fully consume and then move on, filling it with endless content would make it less valuable to me.
Yeah, there is a delicate balance between endless content and "hey, this is probably valuable to you".
Maybe you could even set "I only want to see a maximum of 5 new posts a day" or something like that.
I wonder with the right incentives if this could be run as a distributed open-source service.