I went on a similar diet as yours in December of 2023 following my RALP surgery for Gleason3/4. I went from 192 to 172 lbs (low end of green BMI chart) and blood pressure dropped as well down to your numbers.

I recently attended the Moores Cancer Center (San Diego) PC Summit Conference earlier this year. The doctor presenting on "diet and prostate cancer" said that the good news is that a "Vege' forward diet is clinically associated with a 50% reduction in the rise of PSA". She went on to say that unfortunately there is no correlation to curing PC with diet. Also vitamins have not been proven to be beneficial either in arresting or changing the course of PC.
I asked my UCI surgeon about diet recommendations following my RALP in Oct 2023. He is retired now from surgery, but is directing research at the UC Irvine university. He said that he follows a Mediterranean diet and a low carb protocol as there is "sketchy evidence" that a low carb diet may slow progression of the disease as PC cells have enlarged or (expressed) insulin receptors. They react to insulin which of course is triggered by carb intake which may be why there is an association of diabetic men being more susceptible to "high risk" PC.
You dietary changes have clearly had a positive health effect and may have even slowed your PSA progression however I agree with heavyphil that you may want to consider " plan B" as Gleason scores tend to progress and Decipher scores change with it.