Yesterday I nearly burned my orange pi zero because of the faulty LAN cable, after that, everything I plugged into the expansion board couldn't be detected anymore by lsusb or dmesg, it works fine though if I plug in my thumb drive / usb wifi into the usb port on the main board (Next to the LAN port). How do I know for sure that my expansion board is broken and not the pin headers in the main board ? I'm not an electronic guy I don't know anything about soldering and stuff.

try playing some audio?

mostly everything on the expansion board is "brainless", so if it doesn't work, it's probably your main board

mostly everything on the expansion board is "brainless", so if it doesn't work, it's probably your main board

I haven't tried playing some music yet, are you saying that it's meaningless to purchase another expansion board since it's the pi that's broken not the expansion board itself?

Probably the case.  The expansion connector 95% just converts pins into pretty shaped connectors that you're familiar with.