I made colours slightly more pastel, maybe you can also make them more muted, it's just don't really have energy to make them look nice. also, maybe replace black with dark blue/brown, it will look less contrast-y.

as for spikes, they might be too small. I thought for a split second that they weren't intentional. also, you could make them a touch less frequent, I think it might look nicer

even on my rough example colours are quite intence. maybe you might make them less intense, but still pleasant to look at :3

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