This is one of my pet topics! Having started on an Apple II and now we're here, plus a career that has exposed me to Windows, Linux and Mac as day to day work drivers, I have opinions on this matter.

In short your answer is some kind of Linux, which flavour and desktop manager quite frankly it doesn't matter too much and don't be afraid to look at BSD. With that said I'd recommend if possible sourcing a cheap older laptop and using that to install different distros on, and try them out. You can customise almost anything in Linux and if you are so inclined/retarded, like me, you can lose years playing around with different things which while fun is possibly not the best use of times. But you learn a lot, which is good.

For my part in my personal life I'm a big fan of Ubuntu's LTS releases, and right now I'm fond of Gnome 3 which I find is a very user friendly desktop/window manager, letting people install all kinds of add-ons in a very easy way, letting people set up a near-ideal approach to their desktop based on their needs with a minimal of faffing about. In the corporate space I'm Windows all the way, though I feel the change between 10 and 11 and much prefer 10, and while I think MacOS is the best looking of the three (very high in my list of criteria), by some margin, I am using it for my current job and I find it is the odd one out of the three, some of it's UX choices are difficult to adopt, to put it politely. Today, I feel I will never use MacOS again but I'm sure I've said that before. This time I mean it though. That said I think if I was in some kind of design/artistic kind of work I'd probably be based on MacOS.

IMO it's best to use all three as and where you can, they all have some features that the others don't and much like how learning about the Bitcoin network teaches you about the Fiat approach and Austrian vs Keynesian monetary policies, so does playing with the different OS's help you learn about operating systems and the varying approach to UX. I would love to talk to the Woz about this one day.

Have fun, taking control of your desktop is a relevant analogy to Bitcoin!