I m using Note 10+, my phone battery used to work pretty good. But from few days it's not performing quite well, I feel like there some kind of background activity that drains my battery too fast. Last Night my phone was on 90% but when I woke up in morning I saw it on 55%. Look at the Google app it took 22% in 8hrs.
Do one thing even I had the same problem first check everything like cable, adapter and socket then put your mobile in safe mode n check your charging time If it is normal then it's because of some third party apps or if you still have charging issue visit service centre with cable n adapter