Would it make sense to buy a GPU?

I have installed my first hackintosh yesterday on a PC I got for free. It works...kinda. It has the wrong screen resolution (1600x1200 instead of 2560x1440) and many graphical glitches, as seen in this screenshot of spotify:

https://i.redd.it/z144d77dw4131.png

Here are the specs:

Motherboard: ASUS P8Z77-V LX

CPU: Intel i5-3470 (3.2GHz)

GPU: Intel HD Graphics 2500

RAM: 2x2GB DDR3, 2x4GB DDR3, total 12GB DDR3, 1333MHz

Screen connector: DVI

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macOS Version: Mojave 10.14.5

Install method: I used this guide: https://techhowdy.com/process-to-install-hackintosh-macos-mojave/

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Would it make sense to buy a GPU for this hackintosh? If yes, which one would you recommend?