Ok so here are the outputs from a 4v4 game
GPU load is the issue here. If you look at it, you'll see that it's up and down all over the place. This means that it's not being fully used. If it was maxed out, it would be a fairly flat line at around the 50% mark.
At this point your CPU is almost certainly the limiting factor, and there's little you can do about that (except overclock it, if you have the know-how). You should definitely have room to increase your graphics settings, even though image quality and texture quality are the most important ones for making the game look nice and you've already got them fairly high. It's unlikely you'd notice higher textures on a 1080 monitor unless you zoomed in a lot.
Turning down/off physics will slightly improve CPU performance. In-game AA is demanding, but if your GPU has that much room to spare it probably doesn't matter.