I understand the OP.

I love romantic threads in crpgs. But there are very hard to master.
For BG3:
+ They are playercentric, and do not hard limit you due to gender, alignment, race (or species).
+ Some of them are connected to significant character development.
- They are triggerhappy, easy to start or stop a romance by an "innocent" reply.
- They may dive fast into the "sex" bit and after that handle character development dialogs. A bit like a hippy camp in the 60s.

I remember Aerie and Viconia from BG2. Long and rewarding threads. Especially being able to overcome the alignment difference with Viconia.
The best romance handling in my opinion would be to combine the best parts of BG2, BG3 and Mass Effect.