Anxiety is the worst part of this disease! You have a huge decrease in your PSA, so why even think that you are ADT resistant? If your PSA had gone up, now that would be a different story, but it did not. It’s way down. But you have a more aggressive cancer so it is going to take a lot more to knock it down - either many more months of ADT alone - or what you are currently undergoing - HDR +EBRT.
You probably will not be having any more PSA’s during EBRT and for some months afterward, so put that number out of your mind for now. Just the HDR brachytherapy alone probably already greatly destroyed your cancer’s ability to grow; the EBRT will finish the job and catch any strays that may be on the periphery.
You voiced this concern initially about your low testosterone environment and I think it was pretty well sussed out that we really don’t know what every strain of PCa requires in terms of T in order to proliferate. Maybe more aggressive means it grows in lower T levels? Perhaps - but by no means does that make it want to grow in castrate levels of T or even become castrate resistant - that’s a jump you cannot make.
Just continue on the path you and your doctors have chosen…or in the words of Confucius: “When rape is inevitable…just lay back and enjoy…”🥠🥠