On Mac OS, there are very few options to change the Title Bar focus color. The difference between focused and not focused colors is rather subtle for my partly color blind eyes! None of the available options were much of an improvement. Not an issue on Linux or Windows.
I partly solved the mouse only copy-paste issues with BetterTouchTool. Not perfect, but you can program the mouse buttons, with a modifier key, to do these functions.
I was always confused by Mac's permitting the middle mouse wheel to scroll a NON-Focused window! Yet, this does not change the keyboard focus, and key strokes still go to the other window! I don't see how this makes any sense at all! ANY mouse button should change the focus, not just the left one!
Both Windows and Linux have hundreds of GUI items the user can change and each one has dozens to hundreds of possibilities. Mac OS has a mere handful of changeable items and a handful of possibilities for each. How is this user friendly? I guess, Uncle Steve knows best! NOT!
I've had two Mac Mini's and over half a dozen other computers, over the years. I've had as many hardware issues with the two macs as all my other computers combined.
My first Mac had more serious issues. The disk controller chip went bad and I had to replace the main circuit board. I assumed I had the bad luck of getting one of the few lemons that every manufacturer occasionally produces and bought the second.
After a few years, the second Mac started booting VERY SLOWLY! I googled this and discovered I had to reset the system parameters in the CMOS RAM. I also replaced the battery. Unfortunately, that didn't fix the problem! Every month or so, I had to reset the system parameters, again! Battery backed RAM? Seriously? Hasn't Apple heard of EEPROMs? They've only been around for decades! Apple is usually at the front of the pack applying new technology. What happened here?