is the multiple time factory data reset cause any damage in mobile phone health ?

today i started charging my j7 prime in switched off mode by original samsung charger and adapter .. but after 2.30 hrs charging it only charged 78% ... what is the problem ?

i bought j7 prime last year and it is now in the warrenty period . Main proboems of my phone are .. 1. charging problem __ battery charging is very slow and when it goes 88% then it falls down to 81% then it tooks a lot time to 81% to 100% . why...

I recently bought a new usb cable for charging my j7 prime .. here is the result of charging with new samsung original cable with original adapter of j7 prime ... in switch off mode ... the result of 2.5 hrs charging ... 8.24 pm .... 12 %9.24 pm .......

wow . battery nack up in j7 prime ..