I tend to think the sidhe would do a lot of counterproductive things in their efforts to create a more Glamourous world. It's clear from CTD's texts that they've internalized a lot of toxic ideals from human culture already (for example, hierarchicalism and purity culture), and they're stubborn as hell about the ways they've settled into. It's also clear that sidhe can't really distinguish between things that are actually deep and things that give them big emotions.
I could imagine the sidhe coming up with something like James Cameron's Avatar. Something that's very pretty and evokes awe, but doesn't give people anything that genuinely challenges their white western assumptions, nor offers them anything they can use to change things. Something that seems deep on the surface, but is actually incredibly chauvinistic and backhanded. Something that romanticizes toxic and entitled behaviors. Something that's very, very good for making lots of merchandise that will one day land in a dump.
I can also imagine them promoting a lot of toxic beauty trends in the belief that they're helping people improve their prospects. The text tells us that sidhe embody beauty, and we can see from descriptions and illustrations that the beauty they embody is actually western white beauty standards - tall, thin, pointy-featured. The sidhe don't seem to have much interest in self-reflection or questioning their assumptions, so it's easy to see them becoming influencers who think that encouraging people to imitate these specific beauty standards is going to create Glamour.
(I maintain that the sidhe's beauty shouldn't work on everyone. Some people should find them uncanny. What's "terrifyingly beautiful" to one person can just be terrifying to another. And perhaps the sidhe would evoke distrust in those who are aware of how disingenuous perfect-looking social media influencers tend to be.)
The sidhe's fixation on an idealized past that never existed (if Dark Ages: Fae is anything to go by, very little fae history presented in CTD can be trusted) could make them extremely vulnerable to internalizing and replicating the viewpoints of far right movements that also rely on myths of idealized pasts. There's a lot in these movements that would stroke their egos, and might even be Glamourous to the sidhe. Thus the sidhe would go on to replicate the parts they found appealing, little realizing that they're only creating short-term gains for themselves and a few people while sowing the seeds for an extremely Banal world not too far down the line.
The sidhe as written, I believe, would ultimately be the architects of their own downfalls. They're simply too prone to embodying and furthering ideals that lead to Banality. Should the sidhe ever truly survive, they need to learn that you can't have your cakes and eat them, too.
