How to use Linode for dynamic gitlab-runner capacities

We have quite some bare metal capacity for our own GitLab instance and all customer projects. We do CI/CD daily with gitlab-runner, currently on bare metal infrastructure as well. We're now looking into ways to make this CI/CD more dynamic.

In simple terms, we'd like to run one or many gitlab-runner instances, each of which running one or many jobs inside docker containers. All the pipelines are available, tested and in active use, so that's not an issue. What I'm wondering about is if and how I could launch dynamic capacity on Linode to facilitate the resources required for the current load, which runs 24/7 but with very different load.

Also, K8s is not yet an option, we want to keep it simple for the time being.