IMO I was experimenting a bit with Lightning last night, and I wasn't entirely happy with how this model depicts synthwave/vaporwave. These are cool cats you've made, but they're just not quite entirely what these art styles represent. I'd recommend running the same prompt with basic SDXL 1.0 and see how your prompt might look in comparison. For further reference, here's an image of mine that I'll leave open prompt for you: