To suggest that Kubernetes doesn't fall under the scope of "battle tested" is a bit misleading. As much as systemd? Of course not. But it's not 2016 anymore and we have billions of collective operational hours with Kubernetes.

Just the other day I found a cluster I had inadvertently left running on my macBook using Kind. It literally had three weeks of uptime (running a full stack of services) and everything was still working, even with the system getting suspended repeatedly.