Things I've done is to remove the active grill shutters and run a 180 degree thermostat. Running a thicker oil is advised as well, but won't affect your temps, it just protects your engine better at those temps. Both of those may void your warranty but in reality doing those will not wreck your engine, they can only help. If you plan to keep your truck beyond the warranty period then IMHO you should definitely do both. They will not prevent you from reaching those temps, but your truck will take longer to get to those temps, meaning, if the hills you're climbing are small enough you might not ever hit them again.
You say you aren't pushing it hard at all, but also say you are in 4th gear. I would think 4th gear would be turning a good amount of rpm's and if in any hills would make for some higher oil and coolant Temps.
4th gear at 50 mph is not "pushing it", probably around 3000 rpms.
I’ve read that in some Ram trucks the oil temperature is calculated (estimated) by the PCM, not a real sensor measurement. Do the 5.7 have an actual physical oil temperature sensor?
What about the 6.4?
I read discussion that the oil pressure is calculated, never seen someone talk about the temps. In any case the pressure is not calculated, it's a real sensor, the temps are probably real as well.
Well you will get lots of advice here. I know some people get freaked out with warranty but depending on your location the sooner you go with 5-30 with Lubeguard (moly) the better off you will be if you are towing frequently. Have encountered similar numbers towing and just back off when it goes that high. One of the very few drawbacks of the 1500 3.21.....In reality we spend very little time climbing anyway, right? Otherwise the 3.21 is awesome.
The temps have nothing to do with the 3.21.