budget gaming system

So I'm building my first pc and I'm gonna use it mainly for gaming (CS:GO, GTA V, Rainbow Six Siege, Forza Horizon 4, ...). I am looking to play at high/ultra settings at preferably 80+ fps. I am buying a 1080p 144hz monitor, g-sync compatible (AOC C24G1 or AOC G2590FX). I am buying a 144hz one...