Please perform the following step to resolve slow charging issue:
1- Charge the device with the original charger.
2- Perform Interactive checks through the Samsung Members app (Samsung Members> Get Help> Interactive checks->charger/USB).
3- Run the device in safe mode and check the issue.
4- Check with another USB cable.
For further assistance, register your concern in Samsung members app (Open Samsung members app>click on “+“icon>send feedback>Error report/ Ask Questions).
Team Samsung Members