The game use a custom plugin for saving instead of the default one
Link to plugin:
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I assume it's incompatible with normal save edit, as when I open the save in notepad it also have a different opening structure which might interfere with the editor, I suggest to just install cheat menu plugin to the game if you want to cheat in stuff.
Ark of Artemis save file
View attachment 1208208
Other game's save file
View attachment 1208209
Overwriting save do work tho, so that might be your side