Can’t you just use ExFAT? If it is a modern MP3 player, while it may still list FAT32 as a default, it may very well be able to read ExFAT as well.
If not, if you shove the card in the player, the player may be able to format it?
If not not, shoving the card into a digital camera or a smartphone may perhaps allow you to format using FAT32?
