Keep in mind that the infinite universes still obey conservation laws collectively. I tend to think of it like the number line. There are infinite numbers bet

Keep in mind that the infinite universes still obey conservation laws collectively. I tend to think of it like the number line. There are infinite numbers between 0 and 1. If we decide to define infinite unique ranges between 0 and 1, the space each one occupies becomes infinitely small and the total range is conserved. But we don't know whether the multiverse is infinite or not, so that corresponds to the question of whether the range is from 0 to 1, or 0 to infinity. Either way, the original point stands, and unitarity of the wavefunction (the most notable conservation law) is maintained in Many-worlds. Where people get confused seems to be a mix-and-match of incompatible parts of the Copenhagen and Many-worlds interpretations, where you have both universe-splitting and the non-unitary wave function collapse in the same flawed interpretation.