John Carmack had no hand in DOOM (2016), and was out of iD Software for quite a while by that point, so I have no idea why you felt the need to bring him up.
Oh damn, I actually had no idea. I stand corrected, thanks for pointing it out.
That explains why there was so much hype for how good Snap Map (the level editor) turned out. I remember playing with it for a bit, and it seemed both powerful and super easy for someone with zero experience in it to get something simple but fun going.
id Software has a long history of dysfunctional management that goes back to its inception. It’s probably not fair to single out John Carmack but there was plenty of backstabbing. All four founders left the company on bad terms.