EDIT 3: After noticing that HE had mistakenly assigned the "Zooz RGBW Controller" driver to the parent device, I manually changed it to "Fibaro RGBW Controller" (since that is the brand of my actual device), and immediately noticed an extra paddle called "Set_Warm_White_Level" which has the desired effect of independently controlling the 4th LED strip in my setup.
Thus, this Feature Request is not as urgent, but should at least be considered in the sense that we currently don't appear to have a straightforward way to set (R,G,B,W) discretely all at once!
EDIT 1: On closer inspection of the Parent RGBW device, it vaguely appears the requested functionality already exists (if so, please ignore). I was looking specifically at the Dimmer-color child device, which is where I would have expected to find it.
EDIT 2: Testing of the various SetLevel paddles on the Parent device did not seem to behave in the manner being described below. Notably, the absence of a Set_White_Level tells me the existing actions are more intended for color mixing. To be more specific, performing a SetLevel = 100 always turns on the White channel, so setting (R,G,B) Levels = (0, 100, 0) in hopes of having only the "Green" strip light up, results in two strips lighting up... the White + Green. (Same issue persists even with "HSB Mode" enabled in Preferences.)
Therefore, this request stands as-is.
On my previous hub, it was possible (and easy) to address each "channel" of the Fibaro RGBW LED Controller, which comes in mighty handy if you're driving 4 WW (warm white) LED strips instead of a single RGBW strip.
In my setup, for example, each of the four strips illuminates a different section of cabinetry in my Kitchen. If I wanted Section 1 to turn On without affecting the other three, using the Hubitat's Generic Component RGB driver, I fear that I'd have to calculate just the right HSL/Luminance combination for that to happen.
This assumption is based solely on seeing a single input for each of the paddles ("Set Level", "Set Color", etc.) under Device Details, whereas I was accustomed to having the R, G, B, and W channels split out independently back on my old hub.
Is this possible to accommodate? Or perhaps, a better question, is this already possible using the existing Actions?