I would recommend getting a laptop that the function USB-C PD - this allows you to sidestep the issue of the laptop battery by having a plugged in power source such as high wattage powerbanks to properly feed the laptop while sitting in the classroom. You dont need a cord to reach the outlet but something to go into your backpack and feed from there.
Best examples:
https://www.amazon.com/POIYTL-20000mAh-Portable-Charging-External/dp/B0B4W3Z62N/ref
or https://www.amazon.com/DEWALT-USB-CHARGING-KIT-DCB094K/dp/B09YY1WTHJ
and external batteries: https://www.amazon.com/gp/product/B07XHFFP74/
The first one is a basic powerbank while item 2 and 3 becomes a modular battery pack allowing you to have additional 1.25 to 1.5X battery life while connected to the USB-C PD cord. Granted its adding another 3 lbs to your pack but it allows you to function without need to provide power. However recharging could be better off with a high end multiple USB-C charging bank such as https://www.amazon.com/Charger-HUNDA-Portable-Charging-Station/dp/B0BMG53J1V/ref
This is a 5 port (3 USB C) charger at 245W allowing you to charge 3 large wattage devices quickly.
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.