I am sorry, but you keep repeating the magic oil hypothesis and it is simply not correct. If you have a problem with improper hardening of a camshaft, and the owner like this original poster seems like a knowledgeable guy who keeps up on maintenance, so we can rule out neglect, there is No magic oil or filter that will correct the problem - the cam will fail. Respectfully, if you have ever disassembled a motor you would appreciate better the degree of strength that these components need to have to last. And while proper lubrication is critical to longevity, if the hardening on a cam Or any other component in the valvetrain if off, you are going to have a failure.Lots of theories out there. The most likely is, poor cam or lifter hardening.
However, you can take steps to mitigate this in the future, running a premium oil (instead of royal purple, it doesn't have a great reputation), running a thicker viscosity (5w-30 offers more protection due to greater HT/HS especially while hot), and changing your oil at 5000 mile intervals instead of relying on the meter in the truck. A higher efficiency filter like the royal purple 20-820 or fram xg2 is also widely recommended instead of stock/mopar.
i am not trying to argue, but a tale from my youth to further illustrate: I rebuilt a 1980s BMW 5 series as my first car in the late 1980s. Among other problems, the car had a bad cam and needed a cam and rocker arms. BMW afficianados of that time always attributed these problems to poor oil change practices or to not adjusting the valves frequently enough. They didn’t want to fault BMW and all pushed Castrol as the magic oil to avoid the issue. After I had rebuilt it and had it at an HPDE a few times, I ran into An old timer BMW mechanic who wanted to talk cars. I mentioned the cam and head work I had done and he commented that BMW had a problem with improper cam hardening on the M30b32 and early b34 cams. He said the other reasons were BS, as he had replaced hundreds of them at the dealer.
If our poster has been using a good quality 5w20 or 0w20 oil changed at a reasonable interval, this would not happen to a properly hardened cam. This is a manufacturing defect, plain and simple, unless there is information we do not have thus far. Telling people to buy oil that probably costs $12 a quart is bad information and a waste of money.