To help your video card temps, cool air intake is key. That means adding front fans. Since your case supports 2x140mm fans in front (or 3x120mm), and comes with 1x140mm fan, you can get one more 140mm fan and mount it in front, and one 120mm or 140mm fan and mount it top back. That should even out the air flow mostly, and help feed cooler air into your graphics card fans. You don't have to break the bank when getting these either, you can get decent models for not much money. You could get two static pressure fans up front (help pull air through filters/obstruction), and switch the fan it came with at the front, to top back. Here's a list with some prices for 140mm fans:
https://pcpartpicker.com/products/case-fan/#s=140
I went with CM Masterfan pro air pressure (nonRGB version) for price/performance value but really it's up to you which one you get.
If you mean MSI afterburner for case fan control, are your fans pwm or dc? (4 pin or 3 pin). Are you able to actually control their speed to the point you hear clearly the difference? Where is your single existing front fan positioned. Ideally to lower graphics card temps, you want it to blow air directly on the card and slightly below it (help feed air into card's fans and take away the warm air being expelled by the card on its sides).