I'm assuming you're talking about that viral omegaverse web serial by Whiskerbrush. Honestly, what struck me most wasn't the power dynamics between alpha and omega, but the internal power struggle of the protagonist, Sera, after the rejection. She's not 'the one' for her pack's alpha, so she's shoved into this societal limbo.
The real exploration of identity comes from her having to build a self-concept entirely outside the fated mate narrative. The power dynamics shift from brute alpha dominance to the subtler, more insidious power of social ostracization and economic control. The pack doesn't cast her out violently; they just make her irrelevant, which in its own way is a more terrifying display of power. Her journey becomes about finding agency not through becoming an alpha, but through discovering a personal authority that the pack's hierarchy can't even recognize, let alone quantify.
It's a quiet, brutal take on systemic power.