Install stuff, try and make it better but end up breaking it horribly, and then spend time fixing it. This is how I've learned everything over the years.
I distro hopped for a few years but eventually settled on Arch over a decade ago. It was a lot more difficult to install back then, but it will still get you comfortable with the CLI if you're not comfortable with it already. Also, if you don't know already, Arch pretty much has the best Wiki available and it works with almost all distros since most only differ in package management.
I actually got heavy into Linux during my freshman year of college (2004) back when Linux wasn't supported for most things, so I wiped Windows off of my PC, and forced myself to use Ubuntu for 2 months, which required me to figure out how to install WINE and Microsoft Office. It was a pain, and after two months I put Windows back on it for dual-boot and ease of use purposes but largely used Linux once I got over the learning hump.
I'd suggest setting up a Level 1 hypervisor like VMware or Proxmox so that you can have multiple things running at once independent of each other, but a Level 2 hypervisor like KVM works just as well, but you have to make sure that you don't break the host OS somehow hahaha
I'm a Linux System Engineer now 🤓