Can you elaborate on the basis of your claim. How are apps detecting each other “cross-profile” if we are agreed the sandboxes (app/in-profile) and the profile-walling works?
Are you just saying, for example; Google App 1 on Profile 1 sends a fingerprint to a server; and Google App 2 on Profile 2 sends a fingerprint to a server; and they attempt to match the fingerprints?
Btw, my understanding is most of the “fingerprinting” tools out there are flawed; not they are wrong, but they are just incomplete and therefore not always accurate representations. One example might be going to a fingerprint explorer and rolling a different hash every time - this is actually good because its unique; or rolling the same hash everytime - this can be good if other people are also rolling the same hash (e.g. the Tor model)