My new hobby is Linux, and all that that entails. I've learned basic command line operations and have experimented with all the popular distros out there, usually in Virtual machines. My daily driver is Ubuntu, and I have Virtualbox installed to try out different distros. I typically run the 'live-cd' / ISO to try out the distro before making a commitment to it. Other distros I use heavily are Fedora, Trisquel, Mint, and TailsOS.

I try not to install too much software on them as I like a simple working environment, typically with nothing but a text editor like Sublimetext running, and a browser with the LiveReload extension for doing web development. No npm or NodeJS crap. Just oldskool development.

The 'ROI' if you will of learning Linux is that I have peace of mind that I'm not being spied upon or potentially getting ambushed by various malware, and also: knowing that I am standing on the shoulders of giants. I am super thankful for how far Linux has come along. I remember in the early days having to write scripts just to get my Wifi adapter working, and hours upon hours trying to debug simple shit like printer compatibility errors, etc

Frankly I didn't have the time to focus on Linux in my twenties, and lately in my thirties I have more free time, so I can go down rabbit-holes all day and it doesn't bother me as much.

My Linux installs are very much 'set and forget', as in, you configure them to your liking, and then never have to do that again for a very long time.