u/CECritic

**...**receiving his mother’s approval.

A lot of people think Judge and Sanji’s rejection of his Germa heritage are what prevent him from fully unlocking Conqueror’s Haki. But I think Sanji already overcame that internal conflict in Wano. He proved that his Germa abilities don’t define who he is, his choices do.

What may still be holding him back is his mother. Deep down, Sanji might fear that embracing his Germa powers means betraying her sacrifice or becoming the kind of person she tried to save him from.

I think Sanji’s big Conqueror’s Haki moment will come when he realizes that his mother would still love him and be proud of the man he became. Similar to Rengoku receiving his mother’s approval in Demon Slayer, Sanji could finally let go of that guilt and become his freest, most confident self.

His final obstacle isn’t Judge or Germa, it’s Sanji believing that he didn’t disappoint his mom.

Anyways, that's my theory and I haven't seen anyone mention this angle so I thought I would mention it.