Diagnosed in 2021 and was similar to your situation. Gleason 4+4. I was 71 and healthy. Surgery was never an option as I never spoke to anyone that had a successful outcome. After much research I decided to do proton radiation.
Spoke to an oncologist at Mayo Rochester and was told I was a good candidate for 5 treatments of proton at a higher dose with a Space Oar procedure done prior to protect the rectum. Also did Lupron for 14 months. Side effects for me were minimal - mainly sleep.
Side effects lingered for almost six months after my last shot, but I feel as good now as before the diagnosis. My recent PSA was < .10 so my cancer is in remission.
After the initial shock of knowing I had cancer, I found what I felt was the best treatment for me. Best wishes to you as you do your research and for a successful outcome.