
No matter how many times I read this, I'm a bit confused with previous emperor and FL father ( adopted since the real one died) relationship. All this mess up shit events happened because of the emperor's obsession?

Yep. They exchanged love letters using fake names, at the very least (it was stated the "Esther Penselors" in the letter of chapter 15 was code name for "Hessel Orpenster", the name of the ML's dad, the former Crown Prince). In chapter 17, there is a flashback where the ML's father told the child ML how to monopolize a love interest, and he was talking about what he did to get the person he himself wanted, which we now learn was the FL's adoptive father. And the FL's adoptive father was the only one the ML's father didn't want to kill (he was the only one he tried to save immediately after stabbing him, which he did only bc the FL's father told him he knew all the truth... and the Crown Prince would have never hurt him otherwise)

And the more telling clue: chapter 20, where we see in a flashback that the crown prince even interfered the relationship between the FL's adoptive father and his fiancéé at the time, Leona (who later was forced to marry the crown prince himself, and gave birth to the ML, so she ended up being the ML's biological mother).

Based on the title, I thought their kid go back in time with adult memory to correct all the things that happened on the 1st TL like those baby reincarnation stories. But I was wrong , lol. I hope the kid got those perks just to correct her frustrating mother. Like girl, you revealed to your ex that he is the father of your child and he got an acceptable reason why he was absent for 7 years. You should at least give him a chance to be a father to your kid little by little, if you're too worried that he might disrupt your kid's life. With your poor communication, no wonder the ML got so obsessive.

The brown hair dude who always break up with the black hair dude didn't got beat up. Probably got into an accident while crossing the road because he was so preoccupied and looking at his phone checking if the the other dude message him. He got poor social skills (which is pretty much obvious in the chapters). His break up habit is his way to confirm if his lover still cares and love him.
Now we got the amnesia route