First, note that since you had a prostatectomy 7 years ago, you have no prostate for the development of “… good/healthy residual tissues of the prostate.” So, the answer must be elsewhere.

The official definition of biochemical recurrence following prostatectomy is 0.20 ng/mL. However, it’s best to begin examining options well before that number is reached.

You’ll feel nothing if the prostate cancer is recurring. As others have mentioned, your first next step is a PSMA PET scan to find the recurrence. If you can find it, you can fight it.