As for things to do first, how about expanding the 30-day timeframe for PRs that are actually already recorded and shown in the game, that one has a mere 1041 votes: Personal Records (PR) - option to select beyond 30-day timeframe - implemented June 2022
The trouble with functionalities like the one proposed here is that most people who want to do something like that, probably also want to do something similar for outdoor rides (and other platforms, as applicable) as well. Doing something Zwift-specific seems a bit redundant and might in the end not be all that popular. (Fwiw, I have a bit of the same feeling when it comes to all the social graph functionality in Zwift as well, but at least those parts are already there and function well as they are.)