PD or Iota for my upgrade?

the steady state DC resistance model will tell you what the charger can do - the best performance it is capable of achieving.

That's the point I've been promoting. When I see the PD vs. whatever threads with different users comparing detailed data I try to interject that the results aren't valid unless the input power to the converter is just as carefully measured and documented. It's a shortcoming of the PD converters that this is a factor, but it is what it is. If there's an additional PD-specific issue related to the battery not being a pure resistive load, I've never ventured there. With the many variables associated with the batteries, I don't see how anything short of near lab conditions could provide data that's valid for comparison. I certainly don't have the capability of creating repeatable conditions with a battery.

PD's input power shortcoming leads to a few unique characteristics: (1) With good shore power or an inverter generator (Honda for sure, probably others), it's a a non-issue. (2) With weak shore power or a larger conventional generator, it's a big disadvantage. (3) With a small conventional generator, it's an advantage, allowing the small generator to run the converter at reduced output instead of overloading the generator.