Welcome to the world of indecisiveness...
Is there a "right" decision...no...
Are there "good" decisions...yes

There is data that points to MDT by itself delaying the need for systemic therapy.

There is also data that points to the combination of MDT + systemic therapy increasing PFS and RPFS. Though, a question to ask is, how long is that difference and is it worth the side effects of systemic treatment...?

I am not sure about differences in OS, in part, the data on that is sparse and is difficult given the length of time involved in collecting and determining that. Also, given he rate of change brought about by medical research, irrelevant to decision making...

Age is a factor, I was 57 when diagnosed, some on this and other forums are in their late 70s, early 80s...they may be looking at decision through a different lens

If the decision involves one or the other, questions still remain, which agents -Lupron, Orgovyx, duration...6-36 months systemic therapy, which ADT, which ARI. Will doing ARI monotherapy work, what about the PATCH trial and estrogen...

As to the side effects of systemic therapy, well, again, well known. A question is what side effects would you experience and the severity? Again, not known. In part, the agents and duration of systemic therapy play a role as do mitigating strategies - diet, exercise, managing stress...I never experienced loss of libido, statistics say 80% do while on systemic therapy. I did the Bataan Memorial March 15 months into systemic therapy. I did not experience depression...

So, what are we to do?

The decision you are trying to make can be one of several, each a good decision...

MDT only
MDT + systemic therapy
Playing the long game, aka, do nothing but continue o monitor, decide ,later.

In part, that answer lays in your clinical data, GS, GG, PSADT, PSAV, an genomic testing...

Keep in mind, even today's most sensitive imaging can't see micro metastatic PCa...

I am high risk, so, generally have been "aggressive" in my treatment decisions. That has worked for me, 12+ years, only three on treatment. Life on versus off treatment, the only difference has generally been not what I do but how I feel doing it. I may be an outlier, in both cases I have done less than the SOC time for systemic therapy, have not included an ARI, T has recovered quickly and the vacations have been lengthy, five ears and going on two plus currently...
https://www.urotoday.com/recent-abstracts/urologic-oncology/prostate-cancer/168250-natural-history-of-untreated-prostate-cancer-a-comprehensive-review-of-long-term-progression-patterns-and-survival-outcomes-beyond-the-abstract.html
https://ancan.org/playing-the-long-game-does-your-recurrent-advanced-prostate-cancer-need-treating-nci-seminar/
Kevin