>>1301There is too little information available to give an exact answer. It depends on what the electrical circuit that makes up the led tape looks like.
0-12V regulators are probably not what you want anyway, leds are not like incandescent bulbs in the way that the light output can be easily regulated with a variable voltage.
If it's just something like leds and resistors you might be able to dim the colours by e.g. individually PWM-ing the r/g/b power connections. If you want to string together a few 555's and passives, or go full arduino is up to you.
