I think to that point, if we want to figure out how you get from solarpunk to fascism, you need to consider what it implies by its analysis (or lack thereof) of the actual material reality that's necessary to make the solarpunk vision come true and how that analysis/blind spots coincide with ecofascism.

What's going on that made dilapidated buildings get overrun by plantlife? Is it massive depopulation? Are we idealizing that?

What's the whole idea about self sufficient communities using technology to live in some kind of frontier? Is this class-conscious, or is it just repackaging settler mythology about frontiersmen and Lebensraum?

And maybe the problem with it "just" being an aesthetic is that it leaves the audience to fill in the blanks for those questions, and I think the default answers aren't great.

I'm in the same boat and so I find such charged characterisations pretty jarring. I at least appreciate people imagining a futurist aesthetic that isn't Silicon Valley minimalism, the "Society if" meme or grimy cyberpunk. I ignore any political programs that people tie into it.

Optimally you'd want very dense urban enviroment mostly if not all to make sure as much nature as possible can be untouched and thriving.

Just a heads up that the idea of nature = no humans, or rather, the divide between human spaces and "natural" spaces is also firmly rooted in white supremacy and colonial ways of looking at land and its role in production. Indigenous and global south people, even global north people in some cases have thrived in rural and wild environments while inhabiting them and participating in the biodiversity. The problem isn't people, it's extractivism. And if ecosystems will ever have a chance to recover it will be through regenerative and conscious practices, not by letting fields fallow and forests do their thing while humans live sequestered "outside" of nature.

I disagree pretty hard with dense urban areas being optimal and that leaving land outside of cities "untouched" would be a good thing.

Humans are nature and the entire planet is our home, which must be maintained regularly. This idea that we need to separate ourselves from the so-called natural world in order to protect it seems incorrect based on history. Many indigenous groups maintained thriving forests, grasslands, etc for centuries before colonizers showed up. Many other animals maintain their environments as well; beavers, elephants, etc. Humans are pollinators too!

Obviously we do many horrible things to our environment, but that's not an innate human behavior. We learned to be destructive of our own environment over time and then it was spread everywhere through colonization. Many people went from being just another animal to seeing themselves as special and, largely through religion (not saying religion is bad, just saying it was used as a tool by the ruling class to indoctrinate people), were taught that everything and everyone existed to be exploited for resources. Capitalism is born out of this idea that we are not part of nature.

I think alienation as described by Marx and others after him explains what I'm saying here in a different context and certainly in more detail. I also don't think we shouldn't mostly live in cities of some type, but we absolutely need people out in the world taking care of it. Moreover, I think at least a not insignificant number of humans simply cannot thrive in dense urban environments.

but also wind power which if you'd cared about saving the earth is definitely not something you'd do

That depends. (link is to probably the most principled/scientific solarpunk in existence)

I thought about this line too, but there's also a lot of urban solar punk art or people calling certain talk buildings in Italy and China solar punk

Notice how solarpunk aesthetic envisions a lifestyle completely at odds with its productive forces. No, I don't think your household windmill is going to sustain that level of civilization! You will build 20 MW Chinese wind turbines and you will enjoy your high level of electricity consumption.