Yes, anesthesia-free dentals are a thing. I've had it done to my Rottweilers a couple of times. The thing is it's not that easy on a dog either. It doesn't look like a lot of fun to me. I've been surprised a dog puts up with it - whether it can be done on a given dog depends on whether they will.
And yes, I had an older dog with a collapsed trachea. As you describe, it started with a slight cough. The cough got worse and worse, and eventually his breathing was noisy and labored. He was a Rottweiler I took in when I was doing rescue work and was IMO too tough a dog to adopt out to the kind of homes that come to rescues groups, so I kept him, but he wasn't one to cooperate with vets. I didn't even explore whether anything could be done about it with the vet. We euthanized.
And yes, I had an older dog with a collapsed trachea. As you describe, it started with a slight cough. The cough got worse and worse, and eventually his breathing was noisy and labored. He was a Rottweiler I took in when I was doing rescue work and was IMO too tough a dog to adopt out to the kind of homes that come to rescues groups, so I kept him, but he wasn't one to cooperate with vets. I didn't even explore whether anything could be done about it with the vet. We euthanized.