Johnny wrote: “It appears tenable that kamma is a natural byproduct of craving. I think that’s why the second noble truth is tanhā and never upādāna. Because by the time one performs kamma/sankhara/upādāna, it’s already too late.”
Tanha is not craving: Tanhā – How We Attach Via Greed, Hate, and Ignorance
Tanha is removed via stopping upadana by getting rid of avijja:
Difference Between Tanhā and Upādāna
These concepts require a lot of thinking. Please feel free to ask questions.