The profiles are independently encrypted with a key derived from the user’s profile PIN. If the other profiles are not logged in then their keys are not in RAM (and they get zeroed beforehand so they can’t be read out of unallocated memory).

Even if the bad guys get root via a LPE in a dummy account there are no keys to find and the profiles’ storage are not mounted.

You couldn’t trust the device after that however, who knows what kind of persistent spyware they could have installed.