But the point is, journey and journée are in fact etymological cognates, despite one having shifted semantically. The fact that they're pronounced differently is just a coincidence, and not related to the fact that they have different meanings.
My point is that false friends are blurring the border between the two languages in your brain, they are confusing because they make you think of something in the wrong language. A solution to reinforce the separation of languages in your brain is to only think about them in the context of their own language, as soon as possible.