Coincidentally we also talked at length about how Bioware tackles this in general and I agree that the "sex scene as a reward for pursuing a relationship" isn't great much, just the fact that apparently having sex is the only goal in a relationship, and emphasizing on it without a care about what happens next, is such a reductive immature idea of relationships in itself that it's always a bit cringey. Such can be particularly felt in Assassin's Creed Odyssey, for example, where every encounters has little impact to the story whatsoever, and can all be summarized as being one-night stands. Once the sex part is done, you seldom ever see them or hear about them ever again (unless your name is Alkibiades and you're the best NPC of the entire game, that is). Not that I don't mind much since I can also enjoy roleplaying as a serial bisexual lover, but it... doesn't make most of them memorable much. It can be pretty fun though, but mostly shallow in the end.
However, I do feel that DA:I had some pretty interesting takes on that in particular. For some of them, sex comes first, then relationship after. For some, sex happens several times in the course of the game, relative to different events. For some, sex never happens because of outside circumstances (and also, without spoiling much, because of proper consent not being able to be given) (and that one romance got me GOOD, 4 years later I'm still not over it, help). Overall it really feels like attention was put into writing those relationships, in a way that felt somewhat substantial, genuine and realistic. As much as can be in a video game medium of course, but yeah, I feel it was a really well-done take on relationships, romances and sex.