I did some quick "looking up " about mutations that you have and IA gave me this answer about TP53 . I specifically asked about this one since this tramples SPOP. SPOP regulates AR and BRAF but can not help with this particular TP53 mutation : (. For that reason I concentrated on TP53 .

Emerging Treatment Strategies:

• Combination Drug Regimens: Preclinical studies from institutions like the University of Michigan show promise using dual-drug approaches—such as combining BET bromodomain inhibitors with DNA methyltransferase (DNMT) inhibitors—to slow growth in transdifferentiated, treatment-resistant prostate tumors that have lost TP53 and RB1.
• Platinum-Based Chemotherapy: For aggressive variant prostate cancers often driven by combined TP53, RB1, and PTEN co-alterations, guidelines (such as NCCN) and clinical practice frequently utilize platinum-based chemotherapy regimens (such as cabazitaxel plus carboplatin).
• MDM2/4 Antagonists and p53-Restoring Compounds: Early-phase clinical trials are investigating small molecules designed to block MDM2/MDM4 (which degrade p53) or restore normal function to mutated p53 proteins.
• Genetically Targeted and Delivery Systems: Experimental gene therapies and novel delivery mechanisms (such as targeted nanoparticle or viral delivery of normal TP53 genes) are under early evaluation to re-sensitize resistant cells to standard chemotherapy and radiation.
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I hope this was of any help and perhaps can give you some ideas of what to ask MO. Perhaps platinum based chemo would work better IF this one does not give desired results.

PS: I am so sorry to hear that you could not sleep at all : (((, that sucks big time *sigh BUT your leg is well 🧿🍀 and as always with PC we all have to celebrate small victories *sigh
Wishing you good night sleep and manageable SAs of the third round ! Maybe the "third time's the charm" 👍🍀 !!!