Also considering characters in One Piece and anime announce their attacks all hte time and Japan loves exposition and such. Oda held off Kaido's awakening at least because of Luffy's true DF reveal and awakening I'm sure and we've yet to have a confirmed Yonko awakening which is gonna be even more epic and immense than Luffy's awakening imo, hence why it's being saved until now or so.
I still hold out some hope for BM returning and showing us her awakening. Maybe this defeat and being blown up will force her to awaken if she hasn't before or to use it at least if she awakened already ofc.
Similar to Ichigo's hollow side and Kurama in Naruto, I feel awakening is triggered as a last resort attempt to save the DF users life, the devil inside them from the DF wakes up and makes a desperate final ditch effort to save themselves. Especially if the devil inside has great compability with their user, similar to Kurama and Naruto especially.