Asking for help here isn’t all that much better than shouting about something on a busy local street corner.
When seeking app help, it is usually far more appropriate to ask those that know the app best, that have access to the app servers, and that have the app source code for assistance: the app support team associated with the app.
That’s not us.
The app vendor can see into your account contact. We cannot.
As a suggested solution, if the app is as prone to issues and data loss and instabilities as you believe, and if you believe your messages will be lost if you simply reset a device, and if you are unwilling or unable to receive a response directly from the app vendor, then it is time to replace the app with one of the other fine choices available, such as Signal or iMessage.
Per Contact a third-party vendor - Apple Support: “The best source of help for a product not made by Apple (a third-party product) is the company or person who made it—its vendor or developer.”
Same for providing app feedback. Contact Meta WhatsApp.