What we actually get when we buy Kashmiri chilli is very unpredictable and unregulated. After the extensive research and growing I did 3 -4 years ago (pre-covid) it is most likely that we are mainly being sold Byadgi chillis instead. I have purchased 3 differently branded 1 kg bags of what were supposedly kashmiri chillis and found them to be different in shape, size, colour and heat. I am yet to see a bag of kashmiri chilli powder that exhibits the bright glowing red of some pictures I've seen. Many of them, the best ones, go to the cosmetics industry for use as colouring.
There are hundreds if not thousands of varieties across the subcontinent and the thing is, they cross polinate. The Indian agriculture board has several important varieties listed as recognised while many others are just lal mirch or red chillies.
Robbo, unfortunately for you, the biosecurity into US, could mean that whole chillis are treated in some way to prevent the seeds from germinating. Here in Oz I had one bag of the 3 that produced thousands of viable seeds that produced highly prolific fruiting plants. I only had one plant from another bag and zero from the third.
We are finally in for a hot summer this year and spring is here over the last week. I'll be planting seeds today. The last 3 seasons have been washouts with excessive rain and no sun due to la nina and we finally return to el nino. Hope we don't get the bushfire but we probably will because idiots light them. I bought some seed mix yesterday and I've been weeding out my raised garden beds. Unfortunately, I have very few plants that have survived our first cold winter in over a decade.