For this Lab, what I decided to use was one of the drawers in my dresser; particularly the one where I put my dress socks, bow ties, and video game cases. You can tell in the original picture that even though there’s a good amounts of greys, blues, and reds, there are still pops here and there that overall make it very colorful. For the first black and white shot I decided to use the regular mono setting on my phone’s gallery, and that in turn just made it black and white directly. For the second picture I went into Lightroom and raised the luminance on the brighter colors like hot pink, light blue and yellow. For the third black and white photo I also used Lightroom, but for this one, I opted for also raising the temperature and tone meter alongside bringing down he luminance on other colors like orange and dark purple.
Try the b/w mixer also. For example you could make the red in the beats logo very dark.