I did it again like you said - doesn't work either!Maybe you did it wrong. First boot into twrp/ wipe / advance wipe / select data / change file system / change file system / f2fs / swipe. Then go back to hom / advance/ flash current twrp. Return to hom/ install - select the file twrp-install3.6.0.zip.
0mb internal memory after reboot to twrp.