Replaced battery and charging port but not charging

If the flex cable were faulty would the headphone jack not work either? Because I tested the headphone jack with headphones and it worked.

If the flex is faulty it is not always completely not working some parts of it may still work.

I would replace the charging port assembly and see how it goes. Luckily on this model the charger port is easily removable and doesn't have the button cables wrapping under the screen like the s6 does.

In the note, all of these ideas can be confirmed by the measuring of connectivity, easily measure the contact between input and output and see, if the resistance of the connection is really near to <10ohm. Or, if the USB charging defective, you can do the same, but do not measure the connectivity if your device is under the voltage. Use the Voltage measure to see, if all of the pins are providing specified voltage. Or, measure the USB port → Disassembly it from the mobile phone → connect your USB drive without an adapter → set the connectivity test on your multimeter → first sonde place to the cable USB port (select the wire road) → second sonde place to the output from the USB port. If the resistance is on all roads <10, the charging port is OK.

@Yahziel Cruz