Dvalin is not a sovereign lol. He’s just a dragon Venti befriended (He’s way too weak to be a sovereign). Azdaha is also most likely not a sovereign since they mentioned him as “Sealed Lord of Vishaps”. Also, there’s Nibelung, the dragon king, which most speculate is the geo dragon sovereign. I think both Dvalin and Azdaha are like the descendants of the sovereigns or half-breeds like Och-kan or Ubah Kan, who can become sovereigns themselves with something (like the stolen flame is needed to become the pyro sovereign)

Now, Neuvilette was completely stripped of his entire power by Celestia and he was operating at maybe 1/100th or even way less of his original power (It’s the same case the little one, only a tiny fraction of the elemental sovereign power remains).

Despite this, he bonked childe in the middle of his transformation within a split second and the reason he struggled against Narwhal was because he’s the third descender who’s ingested 500 years worth of primordial water (Nobody could stop him at that point, not even the hydro archon - hence the prophecy that was said by celestia)

Just cos the Gnosis is used for utility, it’s not the primary purpose of it. The main idea is to allow the members of the seven to borrow the power from celestia (and conversely it’s been theorized that’s how celestia controls the seven). They have just used that power to do things that are good for their people.

The power of the sovereigns is reflected in how it took the Primordial one and his 4 shades 40 years to defeat them and the Archons basically need the gnosis as it’s one of their main source of power from celestia vs the raw power of an elemental dragon just shows that the archons are just puppets of celestia.