I'm sorry for your news.

The big question is how many metastases they discovered. If there are just a few, then you're oligometastatic, and they may choose to treat the individual metastases with radiation; if they're widespread, they may choose chemo up front to knock it back a bit. It's also increasingly common to give a "curative" dose of radiation to the prostate, even at stage 4, because studies have shown a significant survival benefit (that's a big change in thinking from 10 years ago).

They'll likely also put you on hormone therapy, including an ADT like Orgovyx and an ARSI like one of the -lutamides or Abiraterone. If your PSA responds to that, then the cancer is still "castrate-sensitive"; if/when it stops responding, your cancer has become "castrate-resistant", and they may suggest other treatments like additional chemo or Pluvicto.

Don't be discouraged. I was 56 when I was diagnosed with de-novo stage 4 prostate cancer metastasised to my spine, and I was certain my life was drawing to a close. I'm 60 now, with no evidence of disease (that doesn't mean I'm "cured", but modern treatments can put many of us in deep functional remission almost indefinitely).