I’m trying to make achievements global, for example, making achievements for different endings in the game
Let’s say I beat the game and get the bad ending, then I beat it again and get the good ending, and the achievements screen will display both as completed
You should be able to do this with global switches/variables, and make your achievements track those switches or variables. For example, by turning a global switch ON when the bad ending is unlocked, and having an achievement track that switch.