That's a lot of food. The nuts and berries don't need reheated at all, and I'd keep those in their own separate container so you don't have to mess about with taking them out of the bigger one before reheating... which still leaves 4 cups of veg+carb and 6oz of meat.

You might just need bigger containers if the primary issue is that you can't get the lid to stay on- Pyrex makes 6-cup rectangular containers and 7-cup round containers.

I'm not finding any containers with multiple compartments that are big enough to accommodate all of your food in one unit. If that's important to you, I'm not seeing a solution that doesn't involve multiple separate containers.