There is something I don't understand, I thought you deployed the WordPress solution in Lightsail and couldn't log in to the application using the password we provide. If that's true, you shouldn't have any data as you couldn't log in, no? In that case, you can simply delete that instance and create a new one.
If you have data, it's because you could log in to the application previously and you can't now, can you confirm this? If you have lost access to the app recently, you can reset the password by following this guide