Is it possible to replace the charging port?

It is possible, but unless you have some experience soldering tiny wires, you may do more damage than good. Lots of shops replace charge ports for alot less than the cost of your phone. If you still want to DIY I’d practice on something else first. You’ll need some tools, so the cost may be no less than just going to a shop unless you already have everything.

As for parts, I usually just buy on Amazon or eBay, but a google search will find plenty of sellers, depending on where you live. partsforrepair.com is a good site for parts too.