iPhone 16 Pro, ProResRAW compatible SSD or drive?

need an external drive to store PRORES files. Have a Samsung 980Pro and Acacsis enclosure 40gbs, but it is only recognized in APFS format and will not save to drive. ExFat will not even be detected by the phone. I swear I had it working last month, but now nothing works. I know there is limit of 4.5watt power draw for the drive, so maybe that's part of the problem. Anybody have any working solutions?