> This means that if you entangle a state with a large system, in theory you could ‘disentangle’ it.
This can be done in any other interpretation? Any unitary evolution on an isolated system can be reversed. This is a mathematical statement.
> Many worlds is falsifiable, if you can show wave function collapse actually happens
So, what experiments do you think would falsify it? How can you show that collapse actually happened?
In the Copenhagen interpretation, when I look at schrodingers cat, the wavefunction will collapse. After I have looked at it, no way to go back. Information is lost. In many worlds, I just become entangled with the system - and I could theoretically disentangle after. Like quantum computing going to a deterministic outcome in a certain basis.
Showing collapse happened is really tricky because of decoherence. Similar to unmixing coffee and milk. But all systems we have observed so far do not show wave function collapse (granted these systems are generally small, but otherwise decoherence starts messing about).
These are just fundamentally different theories. Not just an interpretation, physically different outcomes.