Power is a distribution network, not just total watts. Set an allowed voltage drop per segment, then choose feed spacing and wire gauge. Multi feed bus beats single end feed.
Optics is geometry. Channel depth and shielding do more than “premium” diffusers.
Addressable flicker is usually reference noise. Keep a low impedance return, avoid sharing high current ground with data, add a small series resistor at the source, buffer only if needed.
Quick troubleshooting checklist: https://ledsuntech.com/led-strip-troubleshooting-wiring-selection/