Monterey 12.01 macbook pro fails to charge - is this firmware? Because all cables and supplies work ok

You should install the macOS 12.1 update which is the current update at this time AFAIK.

Try running the Apple Diagnostics to see if any hardware issues are detected.

You need to have someone inspect the USB-C ports to make sure they don't have liquid damage and are not dirty. Many of the Apple USB-C laptops I repair tend to have dirty or damaged ports. It can be extremely difficult inspecting the ports since many times I find issues after removing the I/O Boards (or Logic Board on some Macs).

Disconnect all external devices from the laptop in case one of them is causing a problem. Also connect the charger directly to the laptop since a multi-port adapter, hub, dock may not allow the full power of the charger to reach the laptop.

Try connecting the charger to another USB-C port especially on the other side of the laptop if it has four ports. Try unplugging the charger from the electrical outlet for a minute to reset the charger's internal circuitry. Make sure you are using the actual Apple charging cable since not all USB-C cables will charge a Mac. Even try rotating the charger connector 180 degrees upside down in case the USB-C port is half bad. If you have an Intel Mac, then try an SMC Reset. Here is an Apple article with some troubleshooting tips for USB-C charging issues:

If your USB-C power adapter isn't charging your Mac notebook - Apple Support

You may need to have Apple or an Apple Authorized Service Provider examine the laptop. I highly recommend you ask them to run the service Cooling Diagnostic in addition to the default MRI diagnostic they run since the former can sometimes detect issues the MRI test does not.