If CNCF owns the project now, does that mean they decide the roadmap? Or is that still Kong?
Kuma is an open governance project, so you can get involved, contribute and even become a maintainer: https://github.com/Kong/kuma/blob/master/GOVERNANCE.md
The best way to get involved is by joining the bi-weekly calls as well as the community channels like Slack and GitHub: https://kuma.io/community/