It looks like Cinnamon will give me the best approximation of how my new Windows 10 computer will work. I thought it would be KDE. I figured that trying to get everything to look/behave the same should help, and I’ve got my computer behaving a lot better than it did under Unity already.
I’m using the cinnamon desktop package (pulling in a load of dependencies), with the Windows 10 light theme (installed through Cinnamon), and the Elementary icon set (installed through apt – the package is called elementary-icon-theme).
I suspect at this point I should at least investigate Linux Mint.