I can't comment on the Gladiator aspect but assuming the engine is your main concern it all depends on the year. I have a 3rd gen ecodiesel ('20-'23) Ram 1500 with 55k miles. The main issue with stellantis products are the electrical/software gremlins which manifests itself in the emissions equipment specifically for this combo. We've replaced several sensors and a control module and had good luck overall.
The 1st and 2nd gen engines have been known to have problems with the main bearing going out.
Fuel economy is fantastic and low rpm torque is great for slow crawling. But I'm not sure these are enough to warrant the potential emissions headache.