Hi, the instructions on the wiki for expanding the SD card filesystem need to be updated for f2fs:
I had to replace the "fsck" and "resize2fs" commands with "fsck.f2fs" and "resize.f2fs" respectively for my 64GB sd card. There is some text on that page indicating that the overlay can be ext4 or f2fs, but nothing that describes how to check which one it is, and what commands to use in each case.
There are threads in the installation forum about people having trouble with this, including one just a few days ago (Expand SquashFS on SD Card: error superblock).
Thanks!