I have a similar vintage Air, 4GB. I run Debian+i3, though that’s not everyone’s cup of tea. Machine feels quick, except for bloated websites.
ETA: In case you’re not familiar, i3wm is a lightweight, tiling window manager that is very keyboard-driven. I love it, and you might too! But it takes a little getting used to and definitely isn’t a Windows-esque experience.
First thing I’d do is ditch the GUI file manager: get comfortable with cd, ls, mv, rm, etc.
After that, maybe start with basic text manipulation, like grep, awk, sort, uniq, etc. This ties in nicely with IO redirection, which is essential for a “CLI based workflow.” Get comfortable with pipes and file redirection, it’s extremely powerful!
Writing shell scripts is another super useful exercise: any time you find yourself running the same set of commands multiple times, think about making it a shell script. You may end up with some really useful little custom tools that way.
Not a lawyer; would this likely stand up in court? Obviously I wouldn’t risk it were I the dev, but just curious.
It’s pathetic that I’ll happily recommend my Emporia Vue2 energy monitor to folks running HA — not because it works out of the box, but because the company is aware of the community integration projects and seems ok with it, even if they don’t actually support it. (ESPHome Firmware flash gives you local control — It’s been pretty great!)