This is not medical advice, just some general comments regarding your post.
An upper endoscopy is rarely needed for evaluation for uncomplicated acid reflux. It alone is not even an appropriate indication for an upper endoscopy, except for a specific patient population and that's to screen for a disorder related to acid reflux.
Unsedated endoscopies are uncomfortable for the patient and the physician. They suck. Many gastroenterologists will do it, but there's at least some reason for why others won't. Doctors in countries that do a lot of unsedated upper endoscopies do so because these patients have them much more often (screening for a much higher risk of gastric cancer in, say, Japan). But the way, whether you get anesthesia from an anesthesiologist or no anesthesia doesn't affect how much insurance pays the endoscopist.
The tube you're referring to sounds like pH monitoring with an impedance catheter. It stays in your nose for 24 hours, and generally isn't more convenient than an upper endoscopy. It's not required for diagnosis of simple acid reflux, and serves a completely different purpose than an endoscopy. It's used mainly when the diagnosis is in question. Most gastroenterologists aren't sufficiently trained to read these studies anyway. These patients are usually referred to high volume centers.
A DO, not a chiropractor as you might be thinking. Vast majority of DOs practice exactly the same as MDs, many going through the same post-graduate training.