You sound like you'd be interested in Max Tegmark's "Our Mathematical Universe". There are probably multiple levels of multiverses, and in our local "stack" we

You sound like you'd be interested in Max Tegmark's "Our Mathematical Universe". There are probably multiple levels of multiverses, and in our local "stack" we have 4, where the Many Worlds mechanism is sitting on level 3. Some don't have this level 3, but may have fewer or more levels, using mechanisms foreign to this multiverse, depending on their laws of physics.