Dear Samsung Member,
Greetings from Samsung Customer Support!
Please perform the below mentioned steps to resolve the issue:
1. Check space availability: Settings > Device Care > Storage
Request you to keep at least ''minimum 20% internal memory free''
2. Check space availability: Settings > Device care > Memory
To improve the performance RAM of the device should be free. So, clear the RAM memory once in a day.
3. Avoid usage of mobile phone during charging, Usage of the mobile phone when charging may cause slow charging issue.
For further assistance, register your concern in Samsung Members Application (Open Samsung Members Application > Get help > Send Feedback > Error report/Ask questions).
Thank you for writing to Samsung.
Samsung Customer Support