Hey I don't know if you can swap graphics cards or add a dedicated graphics card in that particular mac, PLEASE do search it up if you can, but here's the deal, you need at least a GTX 1050 which is cheaper than dirt right now... i mean hey not really cheaper than dirt but yes cheap. I have a GTX 1050 ti 4gb from Gigabyte and i can run witcher 60 fps at 1366x768 res all set to ultra except hairworks turned off. 16 gigs of corsair vengence... My processor is i3 9th gen, which is a quad core like your I5, but it's 4.2 ghz turbo.. while your turbo might be at 3 ghz. If you can add a dedicated GPU, you can rock games. Ram for MAC is not cheap, but you can probably add a few more gigs. Get a 8gb RAM if you can, second hand. If you change two things just two things ya know, your GPU and your RAM. You can rock games till year 2019 easily and this game wouldn't be an issue like at all. There's a cheaper option even, if you only want to run this particular game only and usually do non 3d work then you get a gt 1030 ddr5 but in my opinion it's pointless. GTX 1050 is the way to go. If you fail to find MAC upgrades, then feel free to DM me ANYTIME, I will suggest you how to make a cheap, midrange gaming PC. It will serve you like a KING for upcoming years! My current PC cost me less than a MAC and i swear it beats some of the latest MACS. See bro or sis, thing is MAC's are kinda cockblocked from running full performance. They take a 3 ghz processor and cockblock it to 2.5 so it runs cooler. Because MAC's always loved being skinnier than say a PC cabinet. But it ain't practical so lolz on stevie boi. rip