Of course you're not satisfied, who would be. You want your Samsung to work the way you want it to, and my solution doesn't fit your need.
Actually it does, Sony makes a TV set with the circuitry that will do EXACTLY what you want it to do. Samsung doesn't make it on that model.
Tell me, did you have a Thin Profile TV set in your RV before you got the Samsung? How could you, this is the First Year they've been made.
You can't afford it? You OWN an RV.
Look, I can't make you accept my answer, but your not going to be happy with the Samsung when you expect it to have an adjustable volume output on the back of it.
Anything else I suggest is going to be a substandard setup, and I will not suggest anything of that sort.
Now you did state you "just installed" that TV set, I have to assume you "just bought it".
And if you did, you can certainly take it back to the store you purchased it at, and upgrade. Sony isn't that much more costly, and it will do what you want it to do.
Thin profile shouldn't be that much of a deal breaker...you're only talking about the difference of one inch to 3 inches thick.
And yes, Sony makes them if they are a deal breaker.
Listen, my Dad told me years ago to never buy a car you won't be happy with...he was right. I learned my lesson the hard way, and all I can do is pass on that to you. What you do is your choice, all I can do is suggest the solution.