Issues with insurance only covering a specific dental code

Sorry if you've seen this in another sub, I'm attempting to post it to a few different places.

So long story short, I want to get a mouth guard. My TMD/TMJ is so bad that it's to the point where it's giving me migraines. I know I clench and grind at night, but I also have most of the other symptoms, I just don't want to list them all out. (This is long enough lol)

However I don't know if I've ever been "officially diagnosed" While my PCP was doing a physical exam, he touched on my face around under my ears and I jumped/winced in pain and asked what that was and he said TMJ.

My regular dentist is also aware of this as I've told them and actually did get a mouth guard (more on that in a sec) They can tell I clench/grind and I've actually needed my front tooth fixed multiple times because of that. I've had them make a night guard before (like 4 years ago) but I've had so much work on my teeth since then it doesn't fit at all and no adjustment would help. The issue I'm having is with billing and what procedure code they are using. My insurance will pay 80% for SOMETHING. It says codes D7880 and D7881. The issue is my dentist only bills for code D9944. I've asked them if they can do the codes my insurance covers and they said they can't.

So my question is, what can I do/where can I go to find a dentist that bills for that code? Do I just call around and ask places if they bill that code? I've included some pictures. As you can see, they don't cover most things but those two specific codes they do. I've also included the bill from when I got my mouth guard made before and you'll see that the insurance denied it.

Any and all help/advice would be greatly appreciated. Thank you so much!