Unfortunately they’ve largely written themselves into a corner somewhat.
We could see the emergence of the Diamonds and their early interactions, creating the first Gems and settling Homeworld, the shoving of their own moons into the surface make Homeworld’s orbit stable and to get rid of wind and tides, and Pink realizing that Colonization made the other three become serious with her first acting as their own Pearl then their own Spinel until they grew tired of her and gave her a Pearl and Spinel of her own to make her fuck off.
The first Colonies is covered in the Lars adventure, Pink can never have been in charge of anything regarding Colonization or late Homeworld management, and the Diamonds only really have three phases of order and personality during Era 1 that we are aware of.
I suppose you could say that Pink discovered creating Gems or something, since dumping sweat into a hole leading to a vein of natural minerals would be unlikely for the others to try. You could say Pink designed Pearls, which is why the Diamonds made them non-persons in Homeworld rank and why their creation is so radically different than any other kind of Gem. Hell, maybe have a story where Blue is inspired to create Rubies or Amethysts after seeing Pink get attacked by an organic animal and turn it into a fun game of wrasslin’ or something.
Or maybe have the cut Amethyst flashback episode over the Pink reveal, where Pink raises her like she wanted to be raised but accidentally passed on her own inferiority complex, juxtaposed with Pink being treated like a beaten pet after the Diamonds emerged or something.