I think one of the main reasons why ml is so disliked is because of how he first treated fl and was in love with another person. But once he noticed how resourceful and independent fl was, he quickly (like, within a chapter) fell for fl and moved past the person he was in love with before.
I personally think the other suitor part was just a poorly written attempt at creating and resolving conflict. I think he's a pretty reasonable character otherwise.
Also, yay adhd sisters? ><
Thats my beef with it. He was so in love with his ex that (okay well he did nothing because rocks for brains) but he tried to stand up somebody that could crush him like a bug. Then he sees our girl smile like twice and gets all mad she she doesn’t smile for him and suddenly he’s head over heels, oh did I date that one girl i cant cant remember
See the thing is That to me has never really been something that necesarilly deters me in stories like this because more than 3/4 of modern day romance manga and even more so korean romance manhwa start off with the ML being an asshole to the FL and usually no one ever complains or atleast seem to get over it pretty easily. Granted I'm pretty sure (like 97.8%) it's just because since the ML is usually drawn VERY attractively the readers give him a pass. Also I don't know if I have to maybe reread this or something because I definitely don't remember him falling in love in JUST two chapters. Even when he did decide to end things with the other girl it was after rosa helped him see that things where more layered and not as easy as he thought they were which he accepted and realized in a rational way. Heck even he started noticing by all by himself how screwed up the other girl was because she clearly was never told NO as a child. Also...Hi! another nice adhd lady! I salute you fellow soldier

I know that this probably won't change anyone's mind and I 100% understand that but... at some point in my life I was that guy (though I'm a woman) and part of the process of becoming a more dependable and efficient adult I had to learn to be kinder on my past self. I don't want to think I was below someone else's level or that I was not even worth trying to become better because that same mentality is what kept me trapped in that poor state of living. I have adhd and struggled with severe executive disfunction as well as mild depression. 5 years later thanks to occupational therapy I'm in a really happy and healthy place. The chapter where the count realizes that it's not that the ML isn't trying hard enough but rather that his learning curve is different from his, so instead of giving up on him they change the study guide to be able help him. In a weird way this meant a lot to me. I rather see a character genuinly willing and trying to be better than just staying stagnant for literally no reason.