So, the way the "cheat code" works in this game is by checking your input against a pre-set var and if they match, it'll change another (third variable) to 1 and the "cheat code" will be active. So, all you gotta do is to set $userAccess to 1 and your cheats and everything else will be active.
Also, if that's too much work, you can literally open any code editor and look up what the $truePass variable is currently set to (right now it's "I will follow my heart into the darkness").
I personally think that the dev should be supported on patreon, but I also think that the incentive to do so should be actually supporting the dev because you think the game is really good, and not unlocking the ability to have save slots.
edit: also, I just realized, the save slots (and the ability to export/import saves) are unavailable to non-supporters so that they couldn't edit saves to cheat