My Jolla phone has a Samsung Pro 64GB microSDXC card in it (Btrfs formatted, "raw" without partitions). It works well. Samsung seems to call it "64GB microSDHC

My Jolla phone has a Samsung Pro 64GB microSDXC card in it (Btrfs formatted, "raw" without partitions). It works well. Samsung seems to call it "64GB microSDHC Pro" in some places though, so the problem here might be terminology and not actual lack of support. I can't see any reason why the tablet wouldn't support such a card.