Here’s my take on this.
Recovering permanently deleted Messenger messages can be tricky because the data is primarily stored on Facebook’s servers, not just your device. On one hand, your best official route is to use Facebook’s “Download Your Information” feature. This tool compiles all your account data, and there’s a chance the messages were captured in a backup before you deleted them. Also, double-check your ‘Archived Chats’ folder, as it’s easy to archive instead of delete.
On the other hand, relying on Android’s cache files is highly unreliable; that data is temporary and gets overwritten quickly. Third-party recovery apps are also a mixed bag. They often struggle with server-based apps like Messenger and aren’t always guaranteed to work. I’d suggest starting with the official Facebook download method first, as it’s the most direct approach.