Hans, what is your age? That has a big impact on what you decide. If you are older than 70, and with previous health issues, 5 sessions of radiation might suit you best in terms of efficacy and less side effects.
Surgery is still surgery no matter how they dress it up with “robotic”, “nerve sparing” and all the rest. There are still inherent dangers for heart patients especially ( which I think you mentioned).
I chose surgery at age 64 because I was in excellent health and my surgeon said that my Gleason 4+3 unfavorable had a chance of coming back. So I left myself the option of radiation down the road - and just finished with that 5 yrs after surgery.
But to cut thru all the fancy rhetoric and speak frankly, the greater your age, the less your projected life span. Therefore, if you are in your 70’s, have radiation and your cancer comes back (IF!) you might have other serious health issues that may kill you first; and your cancer can then be controlled with ADT if you are still alive.
Remember, the outcomes (success and failure) for surgery and radiation are basically the same - neither is “better” - but one or the other may be better for YOU. Hope this helps!