His kids are acting like normal modern society kids. It doesn't mean that it should go without challenging, but it also mean that you can't expect them to transform into perfect little domesticated children just like our generation were (forgetting that were not half as perfect as we remember).
I don't want to be unkind but you not having children does make a difference because you haven't grown in the last years adapting to this change. I moved with my OH when my kids were 9 and 6 and he too doesn't have children. All was good to start with, but when my eldest became a teenager, he found it hard to deal with the messy bedroom, grunting behaviour, finding her phone more important than humans and responding with attitude.
The difference between the way he and I dealt with it, is that I saw this behaviour as an outcome of them being teenagers of this time rather than an outcome of who they were as individuals. It doesn't mean that I didn't reacted to it, but I didn't challenge it in a way that made them feel they were bad kids for acting this way, but annoying kids being teenagers.
I understand your OH's attitude because the reality is that whatever he does to discipline is not going to make them the image of the perfect kid you have in mind, and attempting to do so will only result in him having a go at them constantly and indeed, take away the loving flow that needs to be in place between children and parents.
All the things you are citing as complaints, 75% of parents will moan about their kids too. As long as you don't give them the belief that they are entitled to act like they rule the place, they are likely to become well adjusted adults, much more so than if you build an environment of tension and stress around them.
My DD is now 17, and almost fully on the other side. She excels at school, has never had an alcoholic drink, let alone drug, is not interested in boyfriend. She works week-ends, study hard to get the 4 A stars she is expected at her A levels and do volunteering at a local club. Yes, her bedroom is still a mess, but frankly, I wouldn't trade any of the good things she does for a perfectly tidy bedroom. DS who is three years younger is following on in exactly the same way.
Still, my OH goes on and on about the state of their bedrooms, and manners, I wish he could focus his attention to how lucky we are to have totally trouble less kids instead.