This Hidden Setting May Help You Read Deleted Messages on Android
A Hidden Android Feature
Deleted messages may sometimes remain visible through Notification History. The feature records notifications received on your phone.
Turn It On First
Notification History must be enabled before the message arrives. On Samsung, go to Settings > Notifications > Advanced settings > Notification history.
Other Android Phones
On other Android devices, open Settings > Notifications > Notification history. Turn on Use notification history. You can also search Settings for it.
Check Deleted Messages
Open Notification History and find the relevant messaging-app alert. If saved, the original notification may show part of the deleted message.
Know the Limits
History only stores notifications received after the feature is enabled. Android may retain notification records for roughly 24 hours.
It Isn't Message Recovery
Muted chats may not generate notifications, while long messages can appear only partially. Notification History can reveal notification text, but it doesn't restore deleted chats.