I usually keep my phone in medium power saving mode. Only to slow down the processor to 70% of the output. While you are at it take the display to QHD, keeping it at FHD has no effect on the battery whatsoever.
Apologies for the delay in response. However, understanding the criticality of the situation; we had to ensure the wellbeing and safety of our employees which led to the delay in response.
Hope your issue is resolved. In case the issue still persists please follow the below mentioned steps.
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. Check app cache a. Clear app cache through Device care : Settings > Device care > Storage > CLEAN NOW b. Clear cache memory of a particular application : Setting > Apps > Now pick the app. For example 'Samsung Internet' > Storage > Clear Cache.
For further assistance, register your concern in Samsung Members Application (Open Samsung Members Application > click on “+“icon > send feedback > error report/ask questions).
