While the decipher score may have something to do with treatment. You can have radiation or surgery with your Gleason 6. Radiation does cause many fewer erectile issues, At least for a few years.

You call it ultrahypofractionated but it actually is just SBRT radiation, No need to use the fancy words when that’s really what’s happening. My brother had a Gleason 4+3 and a couple years ago had five sessions of SBRT and it has worked quite well for him, so far. He did have some urinary issues and had to go on Flomax for a few months, Those problems are gone. It’s very common for people to have five sessions of SBRT,

The decipher score is more intended to tell you how likely you are to have a reoccurrence no matter what kind of treatment you have.

With a Gleason six it’s unusual to have such a high decipher score. Were other things found in your biopsy that you have not mentioned. The question is does your biopsy show things that SBRT radiation may not be sufficient to Eliminate?

Proton therapy is a tighter beam that affects less nearby tissue. Proton radiation is probably going to be the standard in five or 10 years. It used to be they had to build a building for that proton machine, Now they can put it in one or two rooms..

The thing is, it’s very unlikely that SBRT is going to cause issues.

Here’s some more information about how SBRT radiation causes very low incidences of other cancers

Stanford.edu

In a study of about 145,000 men with prostate cancer, the team found that the rate of developing a later cancer is 0.5% higher for those who received radiation treatment than for those who did not. Among men who received radiation, 3% developed another cancer, while among those who were treated without radiation, 2.5% developed another cancer.
https://med.stanford.edu/news/all-news/2022/070/prostate-radiation-slightly-increases-the-risk-of-developing-ano.html