It should be noted that the Everett many worlds model is impossible due to the nonlinearity of gravity - different worlds cannot exist independently of each oth

It should be noted that the Everett many worlds model is impossible due to the nonlinearity of gravity - different worlds cannot exist independently of each other without interacting gravitationally - you’d get the kind of collapse that Penrose’s theory predicted. Given these experiments, there isn’t any obvious theory that squares the kind of wavefunction collapse we observe with the nonlinearity of gravity.