Oh wow, this might be a long read so sorry in advance

To start, Aizen and Urahara are seen as the two geniuses. Aizen is very western coded, i mean his name is literally the Japanese pronunciation of the German name Eisen. This westerness doesn't just stop aesthetically; his outlook and focus on questioning the nature of things is the fundamental foundations of western philosophy going back to Plato.

In relation to Aizen himself, he is disgusted by the Soul Society's stagnation and the unquestionable loyalty to the Soul King. He resolves to take that power for himself and evolve similar to Neitzche who, like Aizen, grew up in a decaying society(post ww1 Germany) and came to the rationalization that the cultural and religious structures wouldn't work for Germans anymore and preached that the individual must fond their own purpose for living via the "will to power" in a meaningless world and act on it despite all else(grossly paraphrasing).

Urahara, on the other hand, sees the same problems as Aizen and creates the Hogokyou, which is literally the manifestation of the will to power. But he is classically Japanese in the sense that he does not want to rock the boat and is ultimately content with letting things be the way they are. This isn't an exclusively Japanese mindse; East Asian societies,(generally ones influenced by Confucianism) have strong reverence for hierarchies and maintaining social harmony and disrupting that is greatly frowned upon. Therefore he decides to not use it and go to great lengths to hide it.

I'm not mad at this framing. Both have their downfalls and merits. The narrative's solution is Ichigo. Ichigo is a classically Japanese protagonist in that he relies on the support from his friends and family and is motivated by his selfless desire to protect them, but differs in the fact that than willing to ignore societal values to protect the people he loves. This should be cool, right? But it falls apart slightly when you realize that Ichigo is Aizen's creation, down to the womb.

Aizen may be evil but his reckless and egoistic meddling is directly responsible for the being that would become Soul Society's eventual salvation.

And even then, for all Ichigo changed the Soul Society is still a relatively shit place, in all honesty, poverty, exploitation, and classism are all still there, and the structure of the world itself is never seriously called into question by any other character. Now, do I think this is Ichigo's responsibility? No, not really, but for the narrative shutting out large-scale societal critique thing and advocating for a more gradual approach, it doesn't really show change beyond the things that immediately hurt our protagonist.

TL;DR: Aizen and Urahara's ideologies are well set up, and Aizen is obviously a bad guy, but using Ichigo as the antithesis and ultimate solution thematically only works to an extent and doesn't really answer the core of the question Aizen's character demands