Just strip it back to the bare essentials. Treat each color band as a channel and feed them through a single shift register or an I²C bus; that eliminates parallel lines. Use PWM to drive the gradient instead of hard‑wired resistors for every shade—one driver per hue, a few duty‑cycles per intensity. Route the traces so they overlap only where they need to, and ditch any duplicated control lines. If you need to keep a microcontroller, make it do the math, not the wiring. Keep the layout linear and avoid loops, and you’ll have a clean, non‑maze circuit that still shows every subtle hue.