It seems this drama has a lot of mixed opinions. HOWEVER, based on what you say you like, I would say to give it a shot. The bromance is the redeeming quality IMO (I did not feel the romance at all). It’s also a very dazzling fantasy. The leads and writer are well known, and it’s got a very high production value.
For full transparency, I personally did not like it. And I usually like fantasy and romance. To prevent anyone from being poisoned against the drama by my opinion I’ll put my review in spoiler text (I will not include spoilers). But, if I had to say why I didn’t like it, it is because a) I did not think the romance was compelling (and I’m usually very tolerant in this regard as someone who watches super low quality rom coms oof) and b) I generally do not like the screenwriter’s works and style. In my opinion, she writes stories that are unnecessarily grandiose and complicated (it didn’t help that TK:EM couldn’t hold my attention so I couldn’t catch all little twists). I’ll watch them but usually I’ll have to stop in the middle and set them aside for a while (same was true for TK:EM, which was definitely my least favorite of her works). If either one is important to you I’d say proceed with caution.
My personal review is negative, but I want to say that I am a big believer that just because I didn’t like something doesn’t mean someone shouldn’t watch it. Just don’t go into it with super high expectations (I think that might have been one of my problems too) and focus on the bromance. If you are tolerant to cringe, you should be fine. More spoilerless review in spoiler text: (because personally for me all the romance scenes were way too over the top and cringe. Probably because I just could never understand why they were together in the first place. Also all the PPL). As a positive thing, I must say that one of my favorite side characters of all time is from this drama. I really loved Jang Micheal.
(In case it’s not clear I put the more negative aspects of my review in spoilers but they are spoiler free. I just don’t want to set people against a drama, even if I did not like it myself.)