This is better but it still doesn't really help when the conflict is 1000 lines and one side changed one character and the other deleted the whole thing. That isn't theoretical - it happens quite regularly.
What you really need is the ability to diff the base and "ours" or "theirs". I've found most different UIs can't do this. VSCode can, but it's difficult to get to.
I haven't tried p4merge though - if it can do that I'm sold!
If I understood your point correctly, I believe that Meld can do that. And then you get a windows as [1]. You can configure git to choose which version goes where. Something like:
So the way you can do it in VSCode is to open the conflict in their smart merge editor... Often it is actually smart enough to highlight the relevant change but if not each of the left/right editors has a button in its toolbar to diff it against the base.
Not the easiest to access but better than copying/pasting (which is what I also used to do).
