I’m not aware of a way to do this currently, but it’s supposedly part of Wyze’s plan for this work-in-progress feature of the app:
Edit: I had another thought: If your goal is merely to be able to see four different camera feeds in landscape at once, then you could try sticking them in the same Device Group and then viewing that Group screen in landscape orientation (i.e., viewing a Group from the Home tab and not using the Monitoring tab at all).