I’m currently in the middle of a renovation so my HA instance is down, but let me give you some pointers. I think it’s possible but it’s getting right into the guts of what makes HA powerful (and complicated)
Firstly, template lights this is how you can surface a light that reads values from other elements and presents them as light settings.
Then the attribute you want is rgb_color and you want to parse out the red value (for the red channel) and convert it to a brightness for the template lamp.
Lastly you’ll need to work how to update the red value of the led strip when the brightness of the light changes. This will involve pulling back the green and blue values of the led strip and updating the strip’s rgb_color with the combined list. this page has examples.
I’m sorry I can’t give you any sample code but this hopefully gets you started.