YEah, I went z6 then z7ii. Mirrorless for me, but that line of lenses is just starting to mature.
D6 is a monster, but in many ways it is designed for spray and pray. By that, I mean what pro news and sports shooters are dying for. 14fps sports at 20megapixels so you can get that shot in odd light, or using those monster fast gigantic lenses you've spent as much on as a used car. All the sorts of things a pro sports guy is looking for that the mirrorless lineup doesn't have native yet.
I wouldn't kick one out of my bed for taking pictures of crackers, but there's no way I'd fully utilize a D6 with what I do. It's just too much camera with a different focus than what I am shooting.