Adoptable storage CAN NOT be read by a computer. FAT32 CAN NOT be read by a phone expecting adoptable storage. You have your choice of one
OR the other, not "and". You've probably lost whatever was on the card by now. Your best bet is to format the card as adoptable storage and leave it that way - if you must. (Remember, SD goes bad a lot faster than eMMC [the internal storage in the phone], and to expand the card, you have to move everything on the current card to the phone, remove the card, install the larger card, then format it to internal and let the phone put things back on it. To me it's not worth it.
External 2 Internal SD (Root) is a better solution if internal and external sizes are different enough. As Samsung says, the technology is made for 3rd world markets, where the common phone has 4-8GB internal storage, and SD card prices have dropped through the floor.)