iPhone 7+ not charging and gets hot when powered on, battery drains

i have had 2 iphone 7+'s (the other one i owned was chewed on by a dog and broke) and this is the first time having this problem. the iphone boots up fine,and runs most apps without trouble, but around 3 months ago it started having problems charging and need to be propped up to charge, and a month ago, it started to get very hot during use within 10-20 mins and uses 20% of its battery in 20-25 mins of use. i purchased this phone in early-mid 2020 as a refurbished phone after my other iphone 7+ broke. I had my other iphone 7+ since 2017 and it didn't have this issue.