stops charging when turns on

hi everyone i have an ipad air 4th gen that will show its charging when off but once it turns on it stops charging or isnt showing the chargeing symble but charges really really slow. ive tried multiple charges and have used differnt power packs and have restarted and factory rested it keeps doing the same thing. im not shore if its coz ive only been able to try 2 of the small square iphone charger packs and the others were Samsung and my dell laptop. and its only happend since i haven been able to use my original pad wall plug because its a usb c connecter to the wall plug