The manifest of my Kubernetes cluster is managed in a Git repository and is automatically deployed via a GitOps tool named Flux CD. When I push changes to the repository, such as adding a new application or upgrading Docker images, the deployment occurs within a few minutes.
This is the way.
Although I use Flux ImageUpdateAutomation instead of Renovate Bot. Did you consider using Flux to do auto updates? Are there any downsides that made you choose Renovate Bot instead?
Just to add to this point. I have been running a separate namespace for CI and it is possible to limit total CPU and memory use for each namespace. This saved me from having to run a VM. Everything (even junk) goes onto k8s isolated by separate namespaces.
If limits and namespaces like this are interesting to you, the k8s resources to read up on are
ResourceQuotaandLimitRange.