Phone won't charge over 1%

Hi recently (before Christmas) I bought a second hand p20 lite for a very attractive price. Then the issues started. The selfie camera got covered in dust very quickly. The phone loves acting up and slow down when I need it the most. But most importantly recently it hasn't been charging very well. I've tried different charges and nothing helps. Finally the piece of rubbish just decided to stop charging. It's stuck at 1% and sometimes even jumps to 0% and then back up to 1%. I am almost certain that it's either the battery or the charging port however I would like to be sure so I don't pay twice for replacements.

Also just so you guys know I have not dropped the phone, haven't put it in the water etc. I've used different chargers and charging cables. I've cleaned the charging port. The only thing I haven't done yet is getting inside of it. Thanks for any help guys

Edit:

Also I forgot to mention that the charging port is not loose and the cable “clicks” in but I have to admit it looks kind of bent from the top (screen side). It's my first encounter with the type-c port so I don't know if it's meant to look like that