Power related issue on Jiayu S3 plus

it doesnt even charge if powered on, so either I set clockspeed to lowest possible frequency or power off the device to charge. I tried killing all background apps, uninstall app that hogs ram too much and turning off all wireless functionality, well it charges but it was too slow, it takes 1 hour to have 10-20%.

Jiayu s3 plus Oreo 8.1.0 v2.1.3