@qu9ke RetropPie will not use the FAT32 formatted partition to store the data. It doesn't matter if your SD card is formatted or not. If you write the RetroPie image on the card, you'll see that will create 2 partitions

a small Fat32 partition to hold the boot files and boot configuration a larger Linux partition that will actually hold the system, including the ROMs, emulators, etc. This partition will be automatically expanded on 1st boot to fill in the rest of your SD card.

So yes, you're overthinking it. Just write the RetroPie image on the SD card and start your Raspberry Pi.