It's not unwatchable, but I skipped many parts throughout this drama as I couldn't care for the side story and characters. Story-wise, this bl was handled maturely (focusing on the main couple). It almost felt realistic in aspects of the relationship between the main couple. They had sex, kissed and mainly respected each other's affection value. Did I mention that they also practiced consent? (This is surprising as many bl don't care to explore this aspect). However, I didn't love how all the couples ended, but I supposed that's realistic, which is okay.
Moreover, the story is nothing new, it's such a simple story, but I think it's done well. Honestly, I recommend you guys to watch this series just for the main couple.