Well, with the clinical data you describe, doing nothing, or what I call actively monitoring through continued labs and consults is an option. I mean GG1, GS 6....

You can plug your lab values into MSKCC nomograms to gather additional data in making a decision - https://www.mskcc.org/nomograms/prostate

You can image with a PSMA PET, it may or may not locate recurrence.

If after gathering all the additional clinical data and discussing with your medical team, the decision is to treat then you have choices:

the PSMA PET is positive, you can do SBRT only to the identified location(s) and then see what happens. There is discussion about SBRT used as Metastatic Directed Therapy delaying the need for systemic (ADT) therapy. Think of it as "spot welding" or "whack a mole."
You could add short term ADT to the SBRT- as others have said, use Orgovyx vice say Lupron. The advantages are:
No flare
Faster to castration
Higher sustained castration rates
Lower CV side effect profile
Faster recovery of T when stopping
No trek to the doctor's office to get the shot, of course, if you get the six months shot vice say a 90 day one...

It does require self-discipline to take it every day and there may be financial toxicity associated with it depending on your insurance. The side effects of no T are familiar, the severity is the question. I've done both, Lupron and Orgovyx, going to say qualitatively, the severity of the side effects were less with Orgovyx.

If the PSMA PET is inconclusive, what then?

Well, back to the do nothing option,,,
Or,,,
You could do radiation to the prostate bed only- SRT
You could include the WPLN with the SRT to the prostate bed.
You could either of those and include short term systemic therapy

Another factor is life expectancy, some studies point to eight years or more before metastases develop.

I have had SRT, WPLN and SBRT, zero side effects, testimony to the advances brought about by medical research in planning and delivery of radiation as well as my radiologist and her team.

Keep in mind statistics, Bell Curve, Standard Deviations, Mean, Mode, Average, Linear Regression. There are guidelines such as the NCCN, AUA. they are based on science but are population based and may lag behind data emerging from ongoing medical research.

The art of medication is applying the science to your PCa.

I can't "tell" you what to do, that's a discussion between you and your medical team. There is no "right" decision from my experience, only good decisions based on the clinical data and the tradeoffs between one decision and another. When faced with a decision, we can easily get mired in "paralysis by analysis...!"

If that was my clinical data, I would do nothing, continue to do labs and consults, wait for a definitive rise in my PSA, three or more consecutive ones spaced three months apart, image between .5-1.0, then decide. In the interim, I would just go about my life, free of the side effects of ADT!

Kevin