simple way to send addressable RGB signal wirelessly
There are various ways to achieve this. In all scenarios I can think of, you would leave the Arduino (or an Arduino, not necessarily the one you have) in control of the RGB lights.
You then transmit some data to the Arduino to tell it what colour to set the LED strip to, and to turn it on or off, or start some other procedure.
The easiest way to do this is probably with the Arduino IoT Cloud and a compatible IoT Arduino board (eg the Arduino Nano 33 IoT). Noting that the Nano IoT is a 3.3v board. Alternately you could use any other IoT board with an IoT breakout board, or my preferred option would be to wait for the new Arduino Nano RP2040 which should be perfect for your use-case.
You could also use a similar board like an ESP32, but they're a little less straightforward to use which, although not really complex, sounds like it might be a little above the level you want at the moment when you're already introducing new skills and technologies.