Hi,
You may be out of luck as far as easy replacements are concerned as the two USB-C port are hard mounted on the motherboard.
Are the ports physically damaged at all?
If not then it may still be a software problem and it may be easier to temporarily replace the battery with a fully charged compatible replacement battery and check the status of the USB-C ports rather than removing the motherboard and to replace the USB-C ports as they may not be faulty.
Here’s the [https://download.lenovo.com/pccbbs/mobiles_pdf/x1_yoga_gen5_x1_carbon_gen8_hmm_en.pdf|hardware maintenance manual] that may help with either option that you decide to go with.