I think the solution is simple: make nebulite crafting a mini-game.
A repeatable minigame that requires user input, and the more you do it, the more your crafting level increases. The higher your crafting level, the higher your chances of getting a higher rank nebulite.
That way botters are completely cockblocked, players have to work for the nebulites and it's a fun new thing to play with. Plus it's an easier way of getting nebulites than what we have now.
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