Cool! I知 glad you found the right truck. I知 sure you値l be happy with the 3.6.
My buddy's got a 2016 Ram (bought new) with the 3.6 and the 8 Speed ZF. His is a little higher spec'd, being an Outdoorsman, but he's been very happy with it. It's a workhorse - he's got about 250 000kms on it right now, and it's required nothing other than basic maintenance. Well, other than the fact that he keeps on blowing out the rear window due to loading his quad in the back of the truck. It's kind of a running joke, I keep bugging him to buy a trailer for his quad, and he just says replacing a window every so often is still cheaper, lol.
I think his lifetime average is around 11 L/100km, but he also does a lot of highway driving - he's got a property out in the country, and does rural sales visits with it.