I like the beast of a machine at https://www.youtube.com/watch?v=sCfmM71NOTo
That's what you need to reach MAX FPS on UHD 4K monitors.
-> Since you didn't reveal what monitor you are choosing I'll start at the best of the best and wait for more from you.
I am planning to buy a gaming PC, budget is around 2500 - 3000, I was wondering what is the best brand and configurations PC I will get with this price. It should be able to run the high end games on MAX FPS (Modern Warfare, APEX, GTA V, Etc.) Please do not copy and paste a link to build my own pc lol