Steam Deck Can't Format SD Cards

So, I got an SD card for Christmas, and my Steam Deck's 'format' button in 'system' was greyed out. I tried to format it via Desktop mode, in which it detected it and it said it worked each time, only for it to be unreadable and unusable in Steam OS mode. So, I buy a replacement thinking its the card, and now it won't format the second card either. I don't know what's up with my Steam Deck, but any help would be appreciated.