hi guys, thanks in advance for any suggestions and answers.

I bought an iMac Pro a couple of days ago. the CPU is 10-cores of Xeon W-2150B, the memory is 64GB, the SSD is 2TB. The speaker is much better than my 2019 iMac. I am an OCDer, I want to upgrade it to top specs and keep it. but I want to confirm some details before I start to do it.

Does anyone know if mine supports 18-Core Xeon W-2191B and 256GB memory? and, it looks very hard to get the Apple SSD like 4tb. Where can I buy 2pcs?