For me Solarpunk is just another concept in a tool box of change. You have Permaculture, Half-earth/Eco Socialism, Degrowth, Circular/Library/Gift/Solidarity Economy etc. — all of them have different aspects of a social, just and ecologically oriented society in mind, they all play nicely together and it’s like choosing a flavour or stacking building blocks. Imho Solarpunk could be a sub category of Degrowth and Degrowth could be a sub category of Solarpunk — both are possible, it just depends on the way you look at them.