Only downside seems to be the Performance of tunnels in Containers.
I use them for my personal Website, did a bit of Loadtesting and was able to get significantly more RPS without the CF Tunnel. Might be something on my end tho, not sure.
Could you please elaborate how and what you know about managed Kubernetes on Hetzner?
I am asking for this since a while and was told there is no way Hetzner would offer such a service. Certain Posts on Social Media have also never been answered with any kind of indication that they are actually working on it.