"Corrupt" SD card after power off?

I have a BQ-7082G ARMOR Android 7 device, with a SD card formatted as internal storage. One day it run out of battery, shut down, and afterwards it reported the SD card is corrupt and refuses to mount it. My only options offered by the device is to reformat it (external/internal storage), something I just won't do because there is some important data on it. Complicating matters I can't easily at least make a backup of the card because I lack a suitable reader to connect to my PC. Side note is I just don't understand how did it get damaged at all? There was no activity for like half a day and the only purpose the device fulfilled back then was to play music. Unfortunately, I got the stupid idea to take some photos with it the day before this happened and I'd like to get them all. Other than that there was no anything else I would lose my sleep over, although getting back everything would be nice. How can I figure out what happened to the card so that hopefully I could fix just that somehow and have the device recognize the SD card properly?