I have a Pixel 3XL on android 10 and a Pixel 3a on android 11. I had previously installed magisk on the Pixel 3a when android 11 was in beta. Recently I found that it had lost root, presumably because android 11 is out of beta and the phone had upgraded to the latest android 11 and was not using the magisk-patched boot image anymore. So, I patched the corresponding boot image for the latest android 11 factory image for pixel 3a, and fastboot flashed it, and it worked.
Unfortunately, I had mixed up my two phones in the fastboot flash step at first, and so then I ended up with the Pixel 3a with android 11 rooted again, but also with the Pixel 3XL stuck on boot, I guess because it had a wrong boot image (for pixel 3a actually) flashed into it. I tried to fix the Pixel 3XL by getting the latest android 10 factory image for it and patching the boot image with magisk. However, after fastboot flash of that patched boot image, it only worked partially. Namely, it could boot, adb shell works, etc., but it no longer responds to touch, so can't be used except for adb shell.
I'm guessing the problem is that I didn't know what was the factory image actually installed on my Pixel 3L, so I just guessed it was the latest, but the boot image from the latest might have some incompatibility with the actual factory image in the phone. I would like to find out what is the actual factory image installed on the Pixel 3L, so I can try to patch the matching boot image.
Hence, my question, how can I know what is the exact version of the android 10 factory image installed on my Pixel 3L? Googling doesn't seem to help, as most pages talk about how to install factory images, not how to find out what is the version installed. In answering my question, please note that I can't interact with the phone now through touch, so cannot check anything under "Settings" with the touch GUI, but can only see the fastboot info (see screenshot below) as well as anything I can access with adb shell (for example, any file in the phone I can check to find out the factory image version installed on the phone?)