See my trail updates thread. It covers lots of AZ trails with the dirt roads not included. The vast majority of those were driven in the 4R on P metric Wildpeaks.
P metric tires are by no means the same across the board, not even close. Nor are E-loads the same. The difference among P-metric tires comes from the shoulder protectors. The Wildpeaks use the same protectors from P to E load. But other tires, like Toyo Open Country AT II, use very mild, style-only protectors in P. As for street tires, those are what they are. Some models like Defender are stronger than others, maybe at the level of generic P metric ATs. But the Wildpeak and its corporate siblings Sumitomo Encounter and Falken Rubitrek stand out to me among all P-metric tires.
Similarly, an E-load Ridge Grappler is nowhere as puncture resistant as a D-load KO2 because the latter has a 3-ply sidewall and the former has a 2 ply.
I asked BFG if their C-load KO2, which has 2 thicker plies is as strong as their D and E versions, which have 3. They said that a tire with a 3rd ply in the sidewall will be more puncture resistant than one with 2.
It stands to reason that LT-C are the best overall fit in that they do offer thicker plies than a regular P metric AT but not as stiff/thick as D/E. However, for my use it is either P or 3-ply sidewall. Although I do plenty of off pavement the middle ground does not suit my use well. I also despise airing up and down because it forces breaks at the wrong place (start and end of trails instead of into the trails).