[Awaiting reply] video freezing issue

I have been troubled with video playback freezing / lagging many times now. I couldn't play videos anywhere either on video player or internet or youtube or social media without it hanging or freezing happens sometimes only while the battery level is less than 40% and all games including the simple ones lags even after a restart or factory resetting . i found out that plugging in the charger and taking it out solves the problem. I think there might be a motherboard issue?? I don't want to again undergo the hassle of backing up the data and resetting it i'm fed up

I've been having one or the either issue since I bought this phone. I made a big mistake buying it