If you pay for an Apple Developer account, you can sideload apps that last 365 days without refresh and install via Xcode or any signing tool.
The most common danger is that the IPA has been injected with malware. Because you are installing software from an unverified source, you are giving that app access to your contacts, microphone, camera, and photos. Hackers often create "fake" Messenger IPAs to steal your login credentials, banking information, or personal photos. messenger ipa
Use a burner account if you must test.
If you are frustrated by the limitations of the official Messenger app, there are safer ways to achieve your goals: If you pay for an Apple Developer account,