Should I just keep VTI and VXUS? I feel like I want a third.

So, I have QQQM, VTI and VXUS currently in my set-up, but I'm thinking of liquidating QQQM and putting it into VTI, but what would replace QQQM? Or should I just stick with VTI and VXUS only? I know I can change it up if need be, but trying to set some gold in stone, if you will, and thx!