And depending on the make of your computer, you may be able to repair it without having to change it. The USBC ports are pretty solid, so it's surprising that they're damaged.

In my experience often the cable might cause the issue. Try with an alternative usb-c cable! Also test alternative usb-c devices before spending money replacing your laptop.

I have no idea. I'm not a computer scientist. The L15 display from Lenovo serves as a second display so that I can work more efficiently. Maybe there is a transition cable USB/USB-C from the laptop to the Lenovo display. Otherwise, just contact Galaxus.