If your doctor says to not go hard, they are the person you should trust. I would have no idea how to make any suggestions about what you should make of your data.
My last almost 70 mile ride had me at 175 max HR with 148 as my average. And the 23 mile ride I just did a few hours ago has me at a max of 170 and average of 148. Both with comparable speeds but your power shows higher than mine.
Still didn't
PR on a climb I've been trying to best. <grin> So I and likely others are envious you can do that with such low HR.