My department is quite outdated in terms of our CI/CD processes, not at any fault of their own but rather due to our dependence on some off-the-shelf software in our stack. As a result, a lot of my fellow team members take a ton of time to test their changes locally due not having stubs/mocks setup. As a result, I took on learning Docker.
While I'm still a junior at Docker, I've been evangelizing it around different teams I work with and offering to dockerize their apps. I even unearthed the "for home projects" Raspberry Pi that was tucked away in my junk drawer and set it up with docker containers as a homelab/PiHole server and for some of my personal projects.
I'm definitely late to the game here but it's honestly one of the best new skills I've picked up this year.