Treatment options for locally advanced prostate cancer?

I have recently been diagnosed with locally advanced prostate cancer in December 2023. I had an MRI that diagnosed my PC with a Gleason 9 stage 4a. My decipher score came back very high with a score of one. My PSA at diagnosis was 26.87 and more than doubled over a two month period while I waited for my initial appointment. I’ve also tested positive for the BRAC1 gene. My PSMA Pet scan showed a very enlarged lymph node in my pelvic region with no other spread to other parts of my body. However my MO has told me I probably have microscopic disease that involves other lymph nodes in my pelvic region. My bone scan showed no metastasis. I’m currently taking Orgovyx + Abiraterone that I’ll have to be on for two years. I’m currently trying to weigh my treatment options. My questions to the group are:
1) What type of treatment did group members with locally advance PC pursue, particularly if a lymph node was in involved?
2)Has anyone with a Gleason score of 9 with local spread had surgery and what has the outcome/side-effects been?
3)I’m looking into Radiation options and my radiation oncologist is recommending IMRT that will include a boost to the lymph node that’s involved. If I moved forward with IMRT and it fails, will I be able to do salvage radiation afterwards? Or are my options limited with this type of therapy?
4) I’ve also been looking into Brachytherapy in conjunction with IMRT and have a virtual consult with a radiation oncologist at UCLA next week. Has anyone selected this form of therapy with a lymph node involvement and what has been the sequence of both therapies and the success rate?
5) Finally, because my cancer is so aggressive I was thinking of doing chemotherapy after I finished my selected radiation treatment for the purpose of killing off any microscopic disease. Has anyone tried this following radiation?