Unfortunately, with Sukkhon in the game, there is no single solution that will suit everybody because there isn't a commonly accepted term for a relationship between a ciswoman and a trans one.
They're both women, so lesbian would seem correct at first, but since the trans woman has a dick, the term gets blurry.
Both "Lesbian friendly" and "Lesbian route" are inappropriate in their ways.
The only thing we can do is accept it, like Yoon's broken English. You understand what she means, even if the wording isn't technically correct.