Q: Should the notification icon display a number of notifications?

The numbers add urgency to the notification icon. These numbers can alter user behavior and increase stress levels by encouraging them to pay close attention to applications. The numbers are a reminder of the number of tasks to be performed. When they test designs with numbered badges, users often emphasize the need to "clean" badges, storing them themselves. This can affect their focus on their workflow or ongoing task.

It all depends on your business model, your value proposition, and the level at which you want your users to stay loyal. If you do not want the user to be unnecessarily connected to your application, go ahead

enter the description of the image here
If you want a constant commitment from users, as in productivity applications requiring immediate action on the part of the user, the numbers can make a lot of sense. Please go for
enter the description of the image here

number 3 is a mix of both which should be your last choice.

Remember one last thing: Users can feel negative feelings if we keep them hooked to an application with little or no value