So this is what I have figured out the best rig for Unreal - I have to plan and earn enough so that I can buy it by 2022 - 2023.
Ryzen Threadripper Pro 5000WX - 2 of these can be inserted in one motherboard, (2-way symmetric multiprocessing (SMP) support.) so a total of 128 cores - meaning 256 threads. (I will probably be able to afford only one at a time, not sure I will even find it at my place or not, but not buying anything below 64 cores)
Motherboard - probably gigabyte or Asus server boards that can support Threadripper Pro 5000WX.
RAM - if I am spending so much I would go with at least 128 GB RAM. Server motherboards can support up to 2 TB.
GPU -GEFORCE RTX 3090 with 24 GB VRAM.
Any suggestions here? I am talking about the best config you can buy.