Here’s what I’m guessing from Luffy melting

Gomu-Gomu no Mi is actually called Nika Nika no Mi which is actually a Special Zoan devil fruit that is based off of Sun Wukong. The amount of beating taken from all of these Kaido fights I feel like triggered an alter-ego from Luffy to become Sun God Nika/Joyboy which changed the properties and classification of his devil fruit but at the same time having all three classifications. (Paramecia, Zoan, and Logia)

Ever since we been introduced to Gear Second and Third from pre-timeskip, and Gear Fourth modes and Red Hawk attacks from post-timeskip, he technically has all three devil fruit classifications.

Gomu Gomu no Mi/Gear 2nd and 3rd - Paramecia Red Hawk Attacks - Logia Gear Fourth (Boundman/Snakeman) - Zoan

I don’t think there ever gonna be an Awakening for Luffy’s devil fruit but more of unlocking the true nature of Gomu Gomu no Mi. You know the actual name and abilities of the fruit. When Oda nem said that once we about Nika is we gonna actually show him but I didn’t think it was gonna be this soon. Also I think Luffy having this new ability is change the whole Straw Hat crew cause Oda did say after Wano Country arc, the Straw Hat will not be the same.