I think there’s a good distinction to be made about the main batboys and murder
Dick: Has killed, could kill again under horrible circumstances, would never want to kill again
Jason: Has killed, could kill under his normal moral code, will definitely be killing again
Tim: Has killed, couldn’t kill again without a major break, doesn’t want to kill again and is willing to kill himself before he does that
Damian: Has killed, couldn’t kill again if people (cough cough DC) respected his growth, and never wants to kill again outside the rare fantasy for especially horrible people
Like all ideas for media this is subjective but I think pretty accurate to these characters as I’ve read up on them and as I understand their characters