Get a few RPis and get https://k3s.io/ running on them. Get familiar with kubectl. Deploy a few apps to your cluster, tail some logs, restart containers, scale them, etc. Install Prometheus, get monitoring working, make some dashboards with Grafana. This point is to gain familiarity with "modern" cloud infrastructure, but in a low stakes environment where nothing can go wrong. Then, you can talk about your experience, and it will technically be true!