Okay so, I am just copy-pasting an explanation of my two cents on this matter I wrote in r/teslore, so it doesn't line up 100% with what you're saying (Since I wrote it with a focus on the Aka-Tusk), but it should hammer the point across, nonetheless.
I generally agree with the notion of all Dragon Gods being shards of a greater entity (The AKA Oversoul, as described in Eat the Dreamer), however I disagree with the Aka-Tusk being said greater entity, mainly because of
Michael Kirkbride's comment on it being an individual, but very primal and important Aspect of the Dragon God from the days of the Ehlnofey. This, in turn, leads to my proposal of it being a composite of Akatosh and Auri-El, before the Maruhkati Selective divided both of them through the Middle Dawn (Assuming they even succeeded), since the "Days of the Ehlnofey" most likely refers to the Dawn Era, where there was no difference between Men and Mer, and all Spirits were effectively the same in divinity.
Now, as I see it, Alduin doesn't necessarily have to the First Aspect that was born from the AKA Oversoul, especially taking in account Kirkbride's statement up above, where he answers the question of whether Alduin was always an aspect of Aka or not by saying that the Et'Ada / Akaspirits as a whole are Quantum Figures which exist in all possible aspects and wear all possible faces simultaneously, with these aspects eventually shedding away from the main entity and gaining self-awareness through the Mythopoeia and Observation of Mortals (He states the same thing in the
Fireside Chats btw, so it's not something he came up with on the fly and will never mention again)
Now as I see it, based on the statements posted above (Kirkbride's comments related to Alduin, as well as the Aka-Tusk stating that Alduin was shed off of itself by some unknown force it identifies as the "Heavens"), in the beginning, the battle of Alduin and Shor didn't really happen between individual Gods with self-awareness of their own, but was more like how the battle between the Aka-Tusk and Lorkhan was remembered by the Nords, due to the ever-fractured and non-linear nature of the Dawn Era (which effectively validifies all versions of the Creation Myth of the Aurbis according to
Nu-Mantia Intercept), and thus, "Shor and Alduin" were basically just other names for these two beings (Lorkhan and the Aka-Tusk). However due to the sheer cultural fragmentation suffered by the Nordic Mythology (Also Known As
the fact that the Religion of the Nords is a mythical clusterfuck), these names were retroactively broken off of the main entities, and became Shard-Beings with faces and self-awareness on their own, perfectly reflecting how the Nords perceived the Dragon God of Time and the Missing God of Change.
