I recently found a solution to that. i found it on android, i guess it will work on other os.
It consists of entering the Data files in the android folder, backing up the folder "com.wotb.tennisace", Copy it and paste it into another folder on the phone, either in Download or Dcim
After you have made a backup of the folder, you just have to give the game data to delete in the settings.
When you have deleted the app data, open the app and close it, go back to the file explorer, copy the backup and paste it where it was before And that's it, you didn't lose your progress