Messages are encrypted on your device so WAMR can't access them directly.
The only solution available is to read them from the notifications that you receive and create a message backup based on your notification history.
When WAMR will detect that a message as been deleted, it will immediately show you a notification!
MEDIA MESSAGES
WAMR will also try to save any media attached to the message and if the sender deletes it, you will receive a notification.
The following media types can be recovered: pictures, videos, animated gifs, audio, voice notes, documents, stickers.
1) Text messages are recovered by your notifications, therefore, if you have put a chat on silence, or if you are currently watching a message on the messaging app before it's deleted you will not receive a notification so WAMR can't save it! This also obviously means that is impossible to recover notifications/messages before you downloaded this app (so download it quickly!).
2) If messages aren't being saved, it may be caused by Android killing WAMR. Please remove WAMR from all battery optimization services!
3) WAMR can't save files if they aren't completely downloaded! So if you are offline or you have an unstable connection, or in general if the sender deletes the message containing a media before the messaging app downloads it, WAMR can't do anything to save it.
4) If you aren't using a WiFi connection, some media may not be automatically downloaded by your messaging app because of your settings. You can change this behavior in Messaging app > Settings > Data and storage usage and increase your chances.