Need help chosing monitor

[Scythe_]

So i am buying a new pc this week but im having trouble chosing my monitor, here are my spec

-i7 7700k

-asus strix 1070ti a8g

-asus z270f

-16gb ddr4 ram

I have a budget of 400-500$ for my monitor, I will use it for gaming (pubg and csgo) and some photoshop.

I am currently looking a the asus pg258q but i am not sure if g sync is really needed.

Please comment some of your ideas i really need help before i buy my new pc.

Thanks

Edit: If its 1440p it would be good