After a year of using my note 9 I've noticed issues like fast changing stopped working adverts popping up in middle of composing emails turns off when battery goes below 10%. Is it a virus or something else you think?
In regards to fast charging @nelsonstars are you able to try another Samsung fast charging brick and cord with your phone and or try your charger with another Samsung phone.
If you use a fast charging pad does it then fast charge ?
A Samsung Experience Store / Samsung Service Centre can run a diagnostic test on the phone.
I agree with @AndrewL that as adverts are not built into the stock apps this is most probably a downloaded app which was free that has ad's built in.
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. " This is the way. "