For everyone wondering why you still got the bug of hp going to 0, it might be because you messed with hp values or other stats on save editor or other cheats. If not, then you need to message the dev on discord server maybe. If yes then either you go back to old saves OR you need to mess a little bit in save editor. You need to go edit your max level to 20 and your current level to 20 too. Then edit your hp and max mana or wtv you edited to a normal value (for example i edited max hp to 120 and max mana to 225)
Then you gotta give yourself AP so that you can turn into normal lvl points AND THEN get your stats higher. This way the game naturally upgrades your stats and the bug wont happen
Hope it works !! :)