It might work still, some brands have tested and gotten 512 and even 1 TB cards to work, but it is entirely unofficial of course.
Back in the day when only 32 Gb was supported, and pretty much also all a regular earning person could afford, well often you could force format ( on PC with a program ) a 64 GB card to be FAT 32 and so work in 32 GB cameras at the time.
Normally a PC / windows will want to format a memory card >32 GB to the Ext FAT file system and not FAT 32, so a trick like that might also be needed with a camera that only support 256GB, but i am guessing here.
256GB is a fine size, with the little i drive a week my footage on full 256GB cards go back 15-16 days.
I will probably soon buy my first 512 GB memory card to test with, but i need to run my 256 GB cards thru a few new hardware cameras to narrow down which brand / model to put my money on.
A 512 GB card today can be had for the price of a 64 GB card in the old days,,,,, the one benefit of getting older / time passing.