Just to chime in I have a 2018 3.5 eco crew cab xlt, bought used at 67k and now has 130k.
In that time the only non wear and tear items I've had to repair or replace has been one of the valve covers cracked, the radiator also developed a leak from the seam at the plastic end caps (these involve a lot more labor hours for a repair then i expected a radiator to have), and right now it needs to have the oil pan seal/gasket replaced as its leaking slightly, but I'm holding off on that till I can buy an aluminum replacement pan that the newer trucks use, instead of the plastic one. I'm sure something will fail eventually, but so far its been great, put plenty of miles on it driving from MN to WY and SD for hunts.
Overall this has been an awesome truck to have, the crew cab is very roomy for the family, I don't like the short box but it works for being in the metro and dealing with parking ramps on campus.