Often a good groomer will be able to get into the dog’s head and accomplish the task with minimal trauma. Using scissors on a nervous dog is tricky, I wouldn’t suggest trying it yourself or allowing a groomer to try unless they are very experienced.
You do not go to the doctor to get a haircut so I would not take my dog to the vet for a haircut. They are not groomers, there is a huge difference. However light sedation might be helpful.
I have been grooming for a lot of years, I rarely run into a dog that I can’t handle. It is what good groomers do for a living! But I stress the “good” part and throw in experienced as well.
I would never have a dog knocked completely out for grooming, that is overkill for sure in my mind.