Screen freeze in game

I am probably the minority here, but I am really annoyed by this so I'm just hoping to find a way to fix this or at least someone to help me suggest ways that I can try. So I have always been using a mac to play, and it has always been fine, but recently I got the new touchbar 15 inch mac, and when I went in game, my mouse cursor was so small. So I realized I have to reduce the resolution of the game in order for the size to fit my screen. My screen resolution for the mac is normally 2880x1800 but I am playing with 1650x1050 in game. I don't know if this is causing the problem, but my screen keeps freezing during the game. At least 5 times a game. And everytime it happens, I don't dc, I can hear everything happening, but my screen just freezes by itself, and I have to minimize it and open it back in order for it to work again. I lost count of the times my screen froze during important fights... Anyone know how to fix this???

Thanks!