Why is the container step slowing down my build?

I noticed that when using the container step, my build is getting slower.

The container step introduces an overhead because internally it is directly using the Kubernetes API to run commands (while without it, only the remoting protocol is used). Therefore, as the container step makes Kubernetes API call, it can be limited by the Max connections to Kubernetes API. This value is set to 32 by default and you can increase it in the Cloud Configuration (under <jenkins_url>/manage/cloud).

To improve the performance of the container step, when using the Kubernetes Plugin version 4526.vdd5315b_e0d0d or later, consider enabling the Use active containers option in Manage Jenkins  Clouds. This routes metadata requests for sh steps inside the container step through the Remoting channel instead of making additional calls to the Kubernetes API.