At least most of that can be turned off in settings somewhere.
Bought a neat closed-loop watercooling cpu heatsink that has a whole dang programmable screen on it if I pay a monthly thing, or solid colors if I don't. defaults to cycling through the rainbow. But it has an off mode, so I'm A-OK with none of that.
It's a problem, but a pretty funny one, to me. Mine does the same thing, startup is full rainbow, then it settles.