So many choices and things to consider.

If you do decide on primary RT, in case of recurrence, salvage RP would not be your first salvage option. (Many years ago, yes that would’ve been your only salvage option.)

These days, if there is local recurrence after primary radiation, choice of treatment would depend on the nature of the recurrence; there are other options - focal therapy (e.g., cryo), brachytherapy, SBRT (because they’re all very targetable), and yes even re-radiation in some cases. Salvage RP would be a distant finisher.

As for the possibility of secondary cancers, those sometimes occur due to overshooting the prostate and hitting otherwise healthy nearby tissues and organs. (Whatever radiation doesn’t hit, it doesn’t damage.) Choose a type of radiation or radiation technology that minimizes overshoot.

As for other possible RT side-effects:
> the possibility of late ED may be minimized by not hitting the penile bulb with radiation. (Again, related to radiation overshoot.)
> the same with radiation-induced proctitis, cystitis, and enteritis - avoid overshoot. Use a rectal spacer (SpaceOAR). SpaceOAR has demonstrated protection against rectal tissue damage, and is also said to protect from late GI and GU toxicities, and provides urinary, bowel, and sexual quality-of-life improvement. (Other rectal spacer options are Barrigel and BioProtect.)

Whatever treatment you choose, go into it fully informed. Whether there are success stories or failure stories, dig a bit deeper and find out the details of what safety protocols they did (or didn’t) follow with their choice of treatment.

(At 65y, I had 28 sessions of proton radiation + 6 months of ADT for a localized, 7(4+3), PSA 7.976, with no other known risk factors. Radiation treatments were relatively uneventful; never experienced ED. We’re now 5 years since treatment; most recent PSA was 0.314 ng/mL.)