This is 150 chapters of slowburn? Just asking

No not at all, the romance starts pretty quickly, it’s really just internal palace drama of who becomes the next queen. And the mc moving up the ranks of concubines. The main story is about to like 119,(or so I think). I like this cause the side stories which are the rest really helps expand their characters a bit especially the king as he gets a bit more personality there.
Overall it isn’t slow burn