Ford has fixed most of the 3.5 common problems and they redeveloped the cam phaser in 2022. It’s still a bit early, but I am hoping the new phasers are good to go. The 5.0 also experienced these issues, but not as frequently as the 3.5. I looked forever for a 5.0 after I sold my 7.3 Tremor, and I couldn't find one. I went with the 3.5 and I am very happy with the truck so far. The 5.0 sounds better, and to date it has been more reliable. The 3.5 has more power and performs better at elevation. They both get similar MPG’s and the 5.0 can be supercharged, providing 700 horsepower. Doing this will void your warranty, but who doesn’t want 700 hp

The 3.5 has twin turbos, which is awesome, but turbos eventually die. Now that I have the 3.5, I really like it and it is a blast to drive on and off road. Tough decision, but for your purposes, it sounds like both will fit the bill. Having said that, I would get the extended warranty and drive the crap out of whatever model you choose. Good luck.