Well... you do not need this setup.
Base model is already a great configuration for editing multiple 4K streams so is future proof for some years of nice work. The Mac Pro also supports 3 4K monitors at 60hz by default. You can update the SSD and RAM with cheaper third party solutions. In January you will see the first 28" quality monitors around $1000 and the bigger ones will be dropping price soon. So the situation is not so bad.