@Dorian Breh
Honestly, I'd look up the return policy for the monitor and GPU. Get your money back and buy the proper 4k GPU.
Save a little money...
Get a slick 4k TV good for TV, gaming, and computer. Rtings.com is my site for research. Vizio are really the best price per inch and performance for gaming and PC when I bought one. It probably still is...
Just make sure you find a TV that can do 1440p at atleast 60 hrtz. Get a comfortable wireless keyboard with TouchPad. Game with Xbox or PS4 gamepad. It's hard to go back.
For cheap games... Go to cdkeys.com