I always thought that artificial languages always needed more stickiness. I learned some Esperanto, but it is easily forgotten if there is no need to use it.

Solarpunk, like many Libertarian Socialist paradigms, really shines with diversity, so languages focused on Solarpunk sound quite weird, like having homogeneous aesthetics. Usually, language changes, like the way Zapatistas talk in Spanish, pursue specific goals that can be done within a language rule set or some mixture between different languages like Spanglish (Spanish + English) or Portuñol (Portuguese + Spanish). The whole point is to be able to communicate a concept.

Now, like the examples you have shown, it seems easier to frame the "Solarpunk language" not as a language per se but as a dialect. Since some geographies share more common communication than between language speakers, it happens in English, Arab, Spanish, French, and Chinese... When you learn to speak those, there is always the question of whether you sound like a foreign person or a native from someplace.