I think for now I will redo my website so it better suite for advertisementAffiliate programs would suit your banners and other forms of cpc quite well actually.
To be more specific, Amazon game code giftcards, G2A (as mentioned above) as well as viral content related to the game (think content.ad or Taboola.)
For Banners you can use any typical eCPM network, but with your volume you could try RevenueHits due to the necessary requirement being fulfilled.
Popups might kill your SEO, but you could try popads or adcash.