Yeah, I ended up checking them both because I *do* think they're different, but also hit some of the same basic id features for me, and could reasonably go under the same trope heading. At the same time, as you were commenting above, you could have two characters who are actual enemies - on opposite sides of a war, say - but don't have E2L interactions if they're immediately friendly with each other.

.... oh, that makes me realize that Delenn and Sheridan are another good example of that! They technically are canonical E2L, but they really don't hit any of the beats of an E2L relationship at all - it's completely friends-to-lovers in spite of their people's antagonism.