By making commits that can be cherry-picked. If one commit adds five different things then you can't add just one of those five things with git cherry-pick.
Then instead of making a second copy and then pasting the code over and commiting it, it's just git cherry-pick and you're done.
Yeah, I know that other people suck and dealing with them is difficult, but this is why there's code review and a company culture. Those soft skills that you think you don't need because you're so smart and everyone else is dumb? turns out they're the smart ones and you're the dumb one for not working on those skills in addition to the stuff you're awesome at because those skills will get them (and you) further in life than any others.
Then instead of making a second copy and then pasting the code over and commiting it, it's just git cherry-pick and you're done.