What can I say...

You could, as @jeffmarc says, initiate the tried but not necessarily true standard of care and do SRT...and "hope" that works... As a friend of mine said long, long ago, "hope is not a method!"

There are choices, in part, may be a function of your clinical data.

Pathology Report
Decipher Test
PSA test results
Genomic Testing

PSA tests results can be used to calculate PSADT and PSAV,
The pathology report gives you clinical data such as GS, GG, SV, ECE, Margins...
It is useful to understand the risk category in making treatment decisions in concert with your medical team.

You can be aggressive in your approach, including WPLN radiation to and short-term systemic therapy. What is short term, may be six months, up to 12-18 though 24 months is in play.

You can forgo the SRT only and let your PSA increase to between .5-1.0, doubling your statistical probability of locating the recurrence and informing the treatment decision.

I am high risk. When I had BCR after surgery (see attached clinical history), I discussed adding WPLN and short term systemic therapy to the SRT. There was data emerging from clinical trials that indicated in high risk cases, the PCa had already moved into the PLNs. My medical team dismissed the idea, no "long term" data supporting it. I acquiesced, you guessed it, SRT was an epic failure.

Would my way have changed the course of my PCa, would I have been cured, we'll never know! The takeaway for me was be aggressive, I have high risk PCa. The next treatment decision, triplet therapy was in part, founded on my mistake with SRT.

That's my experience though. I don't see enough clinical data in your post to inform your decision.

I'm with @brianjarvis though.

Kevin