It's not really hard at all, calculate the max power the leds will draw and get a psu that'll never exceed 90% of that. Your average usage will be waaay lower anyways since you don't usually show all white.
5v power supplies are easily available, Meanwell is a popular & reputable brand. The same psu can run your lights and microcontroller.
5v power supplies are easily available, Meanwell is a popular & reputable brand. The same psu can run your lights and microcontroller.