"The Weave is Mystra, it is the very body and will of the goddess."
It's the blood of the universe, and the weave (thread) are its veins. Wild magic is that blood leaking through.
The first quote is highly contestable.
Is the Demon-Weave the very body & will of Lolth?
Is the shadow-weave the very body & will of Shar?
What does that mean, considering that so many other deities also know the secret methods of utilizing the shadow-weave? Or likewise, the fact that all magic utilizes the Weave, and so therefore, the body of Mystra?
It is said (though I have never seen) that silver fire (mystra) clashing against shadow magic (shar) can tear rifts into the fabric of reality itself. By extension what must this mean? That the body of Mystra and Shar compose reality itself?
All this said, I like that you mention how every spell cast is an act of worship, but for reasons in development, I would point out that it is not necessarily an act of worship to Mystra. As began above, it would not be to Mystra, but instead toreality at large.
This is because it highlights the fundamental nature of divinity and magic.
Consider again, that all magic -- divine or arcane -- utilizes the "weave". Magic as it is, in general, is well documented to be affected, for example, by wild magic areas. Both arcane & divine. The same has been documented of the various cataclysms our world has experienced. Anytime something happens to the 'weave' it (even if to different degrees) affects both (which is to say all) types of magic.
Consider as well, that Mystra's past incarnations have died, yet magic did not die, it simply changed how it behaved. More toward this point later, when talking about Fate.
I would like to draw attention to your language, now. Wild. Rioutous. Rampant. Unrestrained. You used all these words to describe the nature of Wild Magic. This is a recurring acknowledgement of Chaos, which is important when considering the fundamental nature of the universe, above any single God (such as Mystra). This is why I would claim a conflation has been made, throughout recent history. A deity is necessarily a categorical facet of overall reality. This is their ontological domain. A god that encompasses all, would have all domains. Reality encompasses all that has been and all that can be. It is larger than any and all of the gods. That which has been, is certain (though our understanding of it rarely is). Therefore it is a point of potential that has come to rest, and so can be measured or defined. It's Orderly in this way. The uncertain raw potential of the future is chaotic. It is undefined as of yet. It has not come to a single point of rest, by which we can usefully measure it.
Let's look at some more language: Fatidical. This is divinatory, or prophetic, by definition. Fate, and weaving as metaphor for magic, are intrinsically connected here to the ideas of Chaos becoming Order, and the mortal psyche's ability to understand the patterns of those woven strands. In fact, to speak of the essential function of a thing (ontology), divination is exactly that, as revealed by its very name; and names have power.
Divination is an increase in proximity, between the caster's consciousness, and universal consciousness. Their mind encroaches upon the realm and intelligence of "gods" -- the divine. Which, as we are led to believe, and I'll share again, is universally applicable to all magic, because all magic stems from reality, in a sense of the word, "The Weave." So we have this term, Divine, pulling double duty and meaning more than one thing, which contributes to the historical conflation of its truth. I very much appreciate your metaphor in this regard, because while it was perhaps not the most accurate, it still touched upon this profound truth.
It was your metaphor of the body. Your bodily analogy is extremely well articulated. I did not know of this thing called Collagen, but I have definitely seen it at work many times. I think this is the strength of your work, in that it creates very relatable and insightful imagery to draw upon comparison.
Kind Regards, Eluvei Wenchuisel