May not want to swap tire sizes on that Ram just yet..

Don't know about the new Rams in particular but find another dealer.
Better yet find a shop that does a lot of lift kits and big wheels and ask them where they take their trucks.
On my old 13 F250, 3 dealers told me the tpms threshold could not be adjusted. Another issue with bigger aftermarket tire options. Went to Les Schwab and they told me the dlr they use for their customers trucks. Those guys adjusted down the tpms thresholds in like 10 min for me.