We acknowledge your query and apologize for the inconvenience caused to you and will surely assist you regarding the same and please follow the easy troubleshooting steps which might help to solve the issue.
We would like to inform you that please check if you have synced your data with your Gmail or Samsung account then you may retrieve your data. (Go to settings>>Accounts & backup>>Backup & restore>>Restore data)
Check the recyle-bin of your smartphone: Menu>>apps>>phone icon>>three vertical dots>>settings>>recycle-bin>>deleted contacts.
However, if data has been lost accidentally and you have not taken any backup then there is no way to retrieve your data. For the future we recommend you to take back up in the phone.
Install Smart Switch App from Samsung galaxy Store: Data backup process via 'Smart Switch Mobile App'>Open Smart Switch App >Click on Memory Card Icon >Backup option >Choose the data for Backup >Backup.
Import contacts: App's screen>>contactS>>More (three dots)>>manage contacts>>import/export contacts>>import>>SIM card>>Select contacts, for this example tap on all>>done>>google account>>"Import". Your contacts will be saved to your google account and saved to your phone the next time google is synced.
In case the issue still occurs. Please register your concern in Samsung Members Application (Open Samsung Members Application > Get help > Send Feedback > Error report).
Thank you for writing to us. Warm Regards, Samsung Customer Support.
Same thing is happening with me on Galaxy S23 Ultra.
Contacts keep getting deleted from "Google Play Services" when sync contacts was kept enabled, and keep getting deleted from "Null" when this sync is disabled.
