I think transgressive art would challenge principles or unwritten rules on which the solarpunk society is based on. For example, an art piece where everyone who think could do better is entitled to destroy the previous artwork and made a new one. This would promote competition and personal ego over community and waste over reuse. (ok maybe this example is a bit contrived).

If it makes sense to pose such a question? Yes because utopia is not a real thing, it's something you imitate or strive for, as conseguence of this, there would be some people that are not ok with solarpunk (for any reason) and they'll try to challenge this social model.

"I'm going to build my vertical farm/solar panels to put you into perpetual shade. Then, I will put float reflective Mylar panels to steal even more solar." "Enjoy my shade!" /$ For truly transgressive, I will build coal smoke towers, positioned to block your sunlight, and cover everything that you have with soot. Art that reflects this would carry your point across.