There Is no such thing as a true 37” tire unless you buy 40s. That whole thing is an internet myth. What the size on the sidewall says, is what it is. Almost every other tire on the market are within 1/2” of each other.
You have 37s. Its gonna be sweet.
I’ve been on that trail numerous times. Hell I even ran my F150 down it. People not paying attention is where they get in trouble. You could run it in a Subaru. This trail is a case of the pictures are worse than reality. It’s usually the other way around.
Sounds exactly like a battery issue. These things get crazy when a battery is getting bad and these factory batteries suck. I had the same issues on my JLR and replaced the battery with a Oddessy. No issues after that.