Screen flickerig on low battery despite battery replacement

Hi,
Hey i am using my note for a year now, and my phones battery got swelled, with some discussion on xda i was adviced to replace my battery which i did with another original samsungs battery. Now this new battery is charging and discharging fine, and is giving me an on screen time of 5 hours with constant messaging and music and some browsing, the issue that i am having is of battery indication and screen flickering.

First the screen flickering issue, whenever i am below 20 % my screen starts to flicker and it keeps on flickering till the phone dies, sometimes even at 15%. Then when i tried to charge it, it charges from 0.

At times when i partially charge my phone, say i am on 50% and then when i unplug my phone at 60%, it then shows 75% indication but then the flickering starts at 30% and phone dies at 26%.

The battery is giving average time so i think its not a battery issue or maybe it is.

But then i mostly found it a battery indication issue, i read multiple threads and even wiped my battery status. but the issue is the same.