I had the same issue with copy/paste on MacOS, until I couldn't stand it anymore and used software to remap the keys. I swapped the builtin Fn, Ctrl, and Meta keys around so they are positioned like you'd expect on a normal keyboard (and a normal OS), and it instantly fixed my issues without any other negative side effects aside from having to learn another key combo for Ctrl-C in terminals.

I highly recommend the Karabiner app, it makes this change trivial. There's also a way to do it without additional software, described here: https://apple.stackexchange.com/questions/88897/how-do-you-m...