You need memory hooked up to the GPU. Apple’s unified memory is actually one of the cheaper ways to do this. On a typical x86-64 desktop, this means VRAM… for 100+ GB of VRAM you’re deep into tens of thousand of dollars.

Also, if you think Apple’s RAM prices are crazy… you might be surprised at what current DDR5 pricing is today. The $800 that Apple charges to upgrade a MBP from 64-128GB is the current price of 64GB desktop DDR5-6000. Which is actually slower memory than the 8533 MT/s memory you’re getting in the MacBook.