I noticed that her relationship points still can get higher, but the cheat item is not working and neither did the save editor. I dont think it is worth it grinding it manually, especially since it might just not work at all, but maybe you can unlock her if you reach the threshold of her points
yes, the editor was working for me, I also use the on the fly editor (
RPGM_MV_Cheat_Menu_2018-01), allowing you to edit while playing, and tapping the F9 button will bring up the debug, which if you scroll down far enough most of the variables are re-made for the English version, and are in English. ( Can be handy for many thing's.)
But your save is working fine, and was at about the point that I was at or near enough, (
Save number 12 was anyway. I did not check the other's.)