I think this depends on where you run kubernetes and how you set it up. We moved from AWS + ECS to GCP + kubernetes. We use and use terraform to set it all up so that consistency in tooling/patterns helps.

We had one full time senior person doing the move (me) and 6 other coming in an out of the project through the year as their capacity allowed.

One of my clusters is running 5000+ containers with ease. Not huge by other company standards but big enough.