If you get a Ford, try to find one with the max tow package for the reasons that JTW listed. If your getting a EB then stay with 2017 and later. The 2011-2016 was the first gen with some issues.
If you get a Ram, that air suspension they have is pretty damn sweet so look for that option if towing. Also the Ram boxes would be cool.
If getting a Gov Motors truck, good luck....kidding. For sure get the 5.3 at minimum.
Don’t forget about the Titan. (Not the new one). One of my coworkers had a titan that lasted forever and he abused that truck. It was poor on fuel mileage but it was a good half ton.
Tundra might be had for a good deal if you find one with high mileage but has good service records. I wouldn’t be afraid of that.
For the half ton diesels, I’m a little scared of them as they are not built like those for heavy trucks. The F-150 diesel has been around a while in the Range Rover so you can do some research there. That new Chevy in-line 6 looks awesome but first year is scary. The Ram diesel has had some issues but it appears to be improved.
Basically, drive no less than a dozen trucks before you make a decision. You can’t base your opinion of a vehicle just by driving one because it could be a lot better than the others or it could be a lot worse. So at least drive a couple from each manufacturer.
If you decide you don’t to want to go full size, check out the new Ranger with 7500lb tow rating. May be an option.
