I wonder how precise the measurement is. I was concerned about a different (secondary) blood test, but my onco team assured me it was likely just normal fluctuation, not a trend, and indeed it did come back down to normal in my next blood test and the ones after.

From what I understand, for people not under treatment a PSA at or below 2.5 ng/ml is considered "normal" for men in their 40s and 50s, and anything at or below 4.0 ng/ml is "normal" for men in their 60s. Obviously, they're aiming for lower with ADT, but still, maybe you're not seeing the start of a trend, but just a wobble (?)

As always, layperson talking here. In any case, if you reach out, your onco team should make themselves available to discuss any test results you're concerned about and what they might mean.

Source: https://www.hopkinsmedicine.org/health/conditions-and-diseases/prostate-cancer/prostate-cancer-age-specific-screening-guidelines