How do I get to the next quest? The journal says I need to spend time with the girls, but I’ve already done everything, and it still won’t progress to the next quest
So that's the end of the story that's currently in the game. After receiving the underwear from Vanya, there's a message saying the story is over for now, but you probably just clicked past it / skipped this notification
The only thing left after win her panties is to view this in 3D in the player's room while interacting with the closet.