"Dealer set it up pretty nose high despite claiming it was okay and telling me that it would level out with so weight in it."
I don't want to impugn the good dealers and mechanics out there, but this sounds like a weak answer giving him/her an easy out on an issue. I get a little leery when I hear a salesman say "it will be fine IF." or it doesn't look all that bad." How much effort did he put into leveling it? Had your check cleared before he said that?
To be fair, he may very well have done the best he could without some major mods. I have heard some say that the 2018 Rams sit higher that the stock suspension of previous years. I believe they also come with dashboard controls that the driver can use to adjust ride height, ostensibly to increase ground clearance when needed, and "active four corner leveling", which may be their catch phrase for the adjustable height.
You did state your suspension is stock, but consider these issues before making expensive mods to the RV. Just a suggestion. Everyone is talking about adjusting the trailer. That may be trying to fix the wrong issue.