I bought a 400 GB MoveSpeed card for my XA2 Plus after searching the web and finding this page.
It worked fine but later got write-protected and I had to contact the seller and got an exchange…
Anyway I don’t see it senseless to ask for clarification before buying an SD card just for the device.
Unless you count the 32/64GB era, which is now 10+ years ago - and was a filesystem-only thing anyway, there simply are no relevant SD card size limitations anywhere. This makes it senseless to try and insert support specifications when there can’t be any. I don’t understand why Sony lists a made-up “spec”, and a rare size at that.