All the comments suggested are excellent. The big standout for me is that high Decipher Score.
Was there any cribriform/IDC pattern in your biopsy?
That is tough to eradicate with radiation alone so the suggestion of ADT is a good one to weaken the cancer.
Also, you might inquire about HDR brachytherapy in conjunction with SBRT or IMRT. This is short term ( minutes to an hour) high intensity seed placement to blast the worst area since it can be resistant to external radiation alone. It is then followed by a course of SBRT (5 tx) or IMRT (25-39 tx).
Sorry to muddy the waters, but I personally am against surgery at age 74 as well and would like to see you treat this without it. Best,
Phil