Seeking explanation about Jamie Lannister both in books and show…

I’ve watched the show twice over, and it only just dawned on me out of the blue earlier today that he’s crowned the king slayer, but ultimately was still a knight after killing the Mad King… however, virtually never addressed anything about his situation after - like I’m curious if other knights, the public, etc were criticizing his character and title according to the story in the books.

I understand Robert became King, wed into the Lannister family, so I’m assuming the weight of both families and rank essentially granted him a pardon or something, no?

It kinda bothers me now that I’m thinking about it that it wasn’t addressed (or maybe I just don’t remember - and I do remember the bath scene w Brianne, but just don’t remember details similar to what I’m suggesting here)

Would be curious to hear from those who know more than I in this matter