I am also having the same problem. Charger provided with phone box not working, fast charging not working, after a week usb connected/disconnected notification toggles. Please reply back this thread if issue gets resolved.

After then you didn't face this issue again?

I got this problem fixed, what I just did is I kept using the phone till 0%, yes I used till it get switched off automatically. Then I charged my phone till 100% and switched on, tada issue resolved. Now it is working fine as it was just bought.Than...

I am also facing exactly the same issue with my phone Galaxy M30

Yes I am also facing the same problem since last month. Please let us know the solution when it get resolved for you.