I have the same issue, even after reformatting or trying other cards.
Unfortunately, Macs have become more and more inconsistent in their capacity to mount FAT32 partitions, that’s why I had opened a wish for supporting exFAT on any Polyend product.
Unfortunately again, it looks lure this is not technically possible as per Polyend dev team 
So we’ll have to deal with that, and hopefully Windows won’t deprecate FAT32 too much, they already have removed the ability to format in FAT32 by default in Windows 10/11.