Hi, love that avatar. If your OH does turn out to have a hernia or acid reflux or similar those conditions can actually make snoring worse. Mainly because they leave a person uncomfortable and restless with a tendency to try and settle on their back. All of those can make snoring louder and last for longer.
As for the endoscopy, I had one years ago due to unexpained bleeding in the stomach. I chose not to have sedation as I wanted to drive myself to and from the appointment. The worst part for me was the local anaesthetic spray which tasted disgusting it was a really strong banana flavour, the procedure itself was trouble free but I guess a lot depends on the skill of the person doing it.
I was a little concerned when 15 mins or so later I was asked to drink a small cup of water, in the words of the nurse "slowly to start with just in case it goes down the wrong tube" ...eeek I think the nurse had a wicked sense of humour. They do this just to make sure there has not been any tear or damage to the windpipe which of course runs right alongside the food and drink version! It is just precautionary before they let you go home.
My problem was minor and easily treated.
I hope everything goes well and wish you all the best