low gaming performance

I have a ryzen 7 3700x , An asrock b450m board , 32gb ram 3200mhz , a 500gb m.2 and a 3tb hdd , a 3060ti , 750w power supply and windows 10 pro , 144hz lg monitor and it never reaches high temps or bottle necks. The issue i am having is if i run one game it will use 20-40% cpu and gpu max. I can...

So I'm planning to build my first gaming PC ever in order to play GTA V, Witcher 3, and Arkham Knight. Here are the part that I'm choosing for my rig. I'm building this around the motherboard since my friend has a spare one to give for free. Can someone check for me if this build can play GTA V...