Johnnyloans Yeah, in case of forgotten pin code with a pin-locked SIM. Makes sense.
This is all starting to make sense now. I was conflating eSIM support activation (within the OS) with the entire process of eSIM support + carrier transfer/activation. I understand now that I don't have to do both at the same time.
So I'm cautiously optimistic for an easy setup again. I'll probably start the installation tonight. I appreciate everyone's feedback.