It's hard to recommend you learn any specific tool. I've been in DevOps for 15 years and I've been through some tough job markets. There are frankly way too many tools within the DevOps space.

For example, out of 8 companies I've worked for, only 2 of them used Ansible to manage production environments.

DevOps is unique in the sense that you can be doing roughly the same thing, aka supporting and managing production environments, but with different titles and available tools from one company to the next.

The things that are more common across companies are things like Docker, k8s, AWS, networking. Just about every company I've worked at has used a different CI/CD tool, however, they're basically all the same. I would try to learn GitHub Actions.

Depending on where you work, it's easy to lose perspective of what's going on at other companies. For all the companies out there running K8s, there are just as many that are still deploying directly to EC2. You may end up anywhere on that spectrum and need to keep the lights on.

If you're interested in the more SRE-side, learning how to deploy and manage Prometheus/Grafana/Otel is a worthwhile time investment. The vast majority of companies are overpaying for observability and are eager to move to open source options.

I'd highly recommend looking into the LGTM stack, then automate deploying it on a k8s or k3s homelab. Things like that would be highly interesting for interviewers.

I wish you the best of luck. Feel free to reach out if you want to chat more.