
I found it in the comments only, someone had posted a summary of the plot from the novel
Spoilers below.
Basically this is a second timeline where the Mc doesn't have his past life memories (his nightmares are what happened in past life) the ML has his memories which is why he acts how he does (this is the part where I feel if I hadn't read spoilers I'd be so confused by this book)
In short the ML had treated him very poorly in past life which resulted in MC taking their own life (with the gun shown earlier) so ML regretted and prayed them to reincarnate
MC was also pregnant with their child when they died (he was assaulted by the brother so MC didn't know who's child it was but ML knew it was theirs afterwards due to the smell or something)
so probably why ML rn is not okay with being a father rn
So issue now is that ML wants to give him a good life and not repeat the same mistakes but in this universe a paired couple shares all their memories (which is how ML in past life found out that MC was innocent and he mistreated him for no reason before he died)
But if they become paired now MC will get all his past life memories and ML doesn't want that
Ultimately obviously they will become couple and paired then the MC gets overwhelmed by the memories and they break up for sometime
So when I read knowing all this the ML actions made more sense like why he always acts weird about the gun the kids how he knew about stealing the company information his random demands of him quiting company giving bodyguard giving perfume classes etc etc.... but since this is a slow burn I also understand why ppl are not enjoying it since this hasn't been revealed yet

Found that comment here https://www.mangago.zone/home/mangatopic/16846758/
For everyone saying it's a slow burn, I suggest reading the spoilers if you're comfortable with it. I read them before starting the book so the story made more sense to me. I feel if I read it without that I'd be super confused. Also it can help you decide if you wanna continue with the story too if you're on edge of dropping it rn.