
The story is great, but the father is an ass. I can't even see him getting a redemption arc. It just feels unfit now.

Right... usually it's like the jerk male with the redemption arc gets 90 chapters of hurting the main character, realizes their mistake cries for two or three chapters acting miserable, then is forgiven for 3 chapters and its over.... I hope he figures it out very soon and is tortured for 90 chapters for once...

Its human nature afterall, its very evident he doesn't understand the feeling of attachment nor infatuation, and more the less, he definitely just cannot go all soft on Dan immediately, its foreign to him, and this arc makes the all sense. Due to Kim Dans current situation of making jaekyung uncomfortable is quite a nice touch if you think about it..
From personal experience, prideful people tend to notice it late when the situations become real severe. Thats when they start to shift (im an absolute prideful narcissist and its definitely a flaw)
So jaekyung not straining from his old habits makes sense, but you can see a bit of sincerity in his actions.. Just a lil bit yknow lol.

I felt so uncomfortable w/ the scene w/ mc and second ML idk why, they just seem too happy and it just feels weird to me HAHAHA my brain has been completely tampered with chat.

I think because you know that the second ML wont end up with MC, your brain makes it uncomfortable for you to find happiness in their fluffy scenes because that's your mind protecting you from getting hurt when they dont end up together. So it's not because you feel that the red flag ML is the best option for the MC, you know he's toxic. But you know how the story will end, therefore the brain is trying to find ways to cope with the inevitable.
Its too happy to trust.