How is it supposed to be formatted??How is the SD card formatted? And have you checked to see if the SD card is fake or not?
I used the guide and I didn't notice anything special about formatting in any certain way.
I tried 6 different micro SD card from 512MB all the way to 128GB
As to formatting I tried exFAT, FAT32, and whatever real Nintendo Switch formats (as I mentioned I formatted with another NSwitch just to be on the safe side)
And no, I don't think any of them are fake, They all were purchased from legitimate websites, None from weird 3rd party stores or eBay.