Unfortunately you will have to go to Chinese manufacturers for the decent GaN chargers.

The X1 Extreme Gen 2 original charger is 135W so a USB-C PD power source will have to be 100W as a recommendation to charge the laptop and perhaps cover some of the power needs such as running the dedicated GPUs, you may find yourself in a position where your battery will still have to discharge or haul around the 135W charger.

With many devices you want to look at some high wattage chargers:

Example: https://www.amazon.com/Charger-HUNDA-Portable-Charging-Station/dp/B0BMG53J1V/

I have this and its over kill for my needs but having higher wattage means the charger doesn't feel like a heater when using it. This is triple USB-C with dual USB-A ports putting out a maximum power of 245W. For the USB PD cable

https://www.amazon.com/dp/B0BV9BNXL8/ This is a retractable cable, allowing for faster cleanup and less hassle on putting cables back together.