Dust might have entered near Vibration motor,If it's under warranty it'll be repaired for free if not atleast 400 to 500 u have to pay. I've faced same issue in my A52..
Thank you for sharing your concern. We acknowledge your query and apologize for the same. And please follow the easy troubleshooting steps which might help to solve the issue.
1. Menu>apps>settings>sound and vibration>vibration pattern>choose the vibration pattern of your choice.
2. Swipe up the home screen>settings>tap sound and vibration>tap "vibration feedback" to enable it or disable it. Note: When the switch turns blue it means the vibration feedback feature has been enabled.
3. Kindly perform the interactive check of vibration in the Samsung Member Application (Samsung member app>>Get help>>Interactive checks>>Vibration).
In case the issue still occurs. Please register your concern in Samsung Members Application (Open Samsung Members Application > Get help > Send Feedback > Ask question).
Thank you for writing to us. Warm Regards, Samsung Customer Support.
