Can you clarify have you used another Samsung Charger that has fast charging capabilities ?
Can you try a wireless fast charger.
Sometimes a soft reboot by turning the phone Off and On helps.
As a last resort back up and remove any Sd card and factory reset.
A Samsung Service Centre or Samsung Experience Store can run a diagnostic test on the phone.
Daily Driver > Samsung Galaxy s²² Ultra 256Gb in Phantom Black.
The advice I offer is my own and does not represent Samsung’s position.
I'm here to help.
