Unless you yourself have a good and detailed understanding of quantum mechanics, and have solved the Schrodinger equation for many different systems, I'd recomm

Unless you yourself have a good and detailed understanding of quantum mechanics, and have solved the Schrodinger equation for many different systems, I'd recommend not assuming that the physicists who proposed many worlds did so out of some psychological need to have the universe look like a branching tree. The true situation is that the Schrodinger equation straightforwardly predicts a proliferation of worlds when you start from a low-entropy state. (Worlds in this interpretation are actually continuous blobs of amplitude, not discrete objects, which is why it makes sense that a partial differential equation like the Schrodinger equation can describe them. The prediction is that blobs will tend to spread out, split into smaller blobs, etc.) Early quantum physicists were disturbed by this, and added a collapse postulate claiming that the wave-function will sometimes spontaneously collapse, resulting in a single, linear world history rather than a branching one. To this day, spontaneous collapse has never been observed in an experiment.