I've tried the passkey feature in mSecure, and it works well in most cases. However, I encountered an issue with WhatsApp. When creating a passkey, WhatsApp masks part of the phone number, displaying only the last four digits. As a result, if two WhatsApp accounts share the same last four digits, the passkey works for the first account but not the second. If you try to create a second passkey, it overwrites the first one instead of creating a separate entry. Currently I have a workaround - using mSecure for one passkey and Proton Pass for the other passkey.