iPhone X may have over heated and fried mother board?

I was on my iPhone X one night, using a charger I bought from Dollar General until I could get to Walmart to get a new Apple certified, and it was getting hot and then the screen just went blank. Wouldn’t turn back on or anything. Plugged into my computer and the computer didn’t even recognize it. Went to my local Apple certified store, and they said I would need to send it into Apple. Needless to say, I didn’t and I just bought an iPhone XS Max about 8 months later. Wondering if there was somewhere I could get a motherboard possibly, or someone who knows how to fix them, possibly fix it? Not looking to spend a boat load of money. but I really want to get it working again. If you have any suggestions please let me know!