Phone is only charging when in bootloader, but not when turned on/off!

For some reason, the phone is only charging when in bootloader, but not when turned on/off!

when turned on, it will display that its charging but the battery percentage never goes up at all even after hours.

when turned off, it will display the lightning in the batter for maybe 5 seconds, then switch to an exclamation mark with no percentage below.

What's wrong??? Is there any reason that the bootloader, with the screen (the white screen, which I assume is super power hungry) on all the time, allows for more efficient charging?

Another weird thing about is, if I clean the charging port with alcohol, it will charge normally for maybe half a day, and the problem comes back again.