I came across my old Pixel 2XL device today which was discarded long ago due to its charging issues. It stopped charging mysteriously and then went into storage as its battery went to 0% permanently.
I had some free time at my hand today and tried out restoring it to its original image with which it was launched to see if it makes any difference to the charging issue.
Here are the steps which I followed.
Get your device in fastboot
Launch the bootloader/fastboot mode by pressing the volume down and power button simultaneously after removing/connecting back the power.
Fortunately my Pixel 2XL came up in this mode, the battery still had some age left in it.
fastboot devicesDidn't show up anything.
Checked in Device Manager
One entry "Android" showed up with missing driver icon.
Downloaded the Google USB Drivers from below link.
Right click on the "Android" entry in the Device Manager and update driver by pointing to the path of downloaded driver folder above.
My Pixel 2XL showed up in the fastboot devices list at this point.
Unlock the bootloader
Enable Developer Options as described in below link.
Unlock the bootloader with below fastboot commands as described in the link.
https://source.android.com/docs/core/architecture/bootloader/locking_unlocking
fastboot flashing unlock
Download and flash the Image
Download the required image from below link.
I downloaded the first Pixel 2XL image with which the phone was launched.
Unzip the image zip file, and launch the flash_all.bat script.
Did it help?
Surprisingly I was able to get over the charging problem of the phone, albeit at the cost of older Android version with its security risks, and legacy UI. These are acceptable to me since I don't plan to use the phone for anything other than developer experiments.
But these might not be acceptable to you, as it is highly recommended never to use an older Android version for any real usage of the phone due to the missing security patches.