For my get pushed I was challenged to find a tool on any one of my cameras that I have never used before. Although I had tried selective colour in camera before I wondered why I have not used it since.
Well I can tell you now it is such a faff and so much easier by editing later in LR or Snapseed.
I have done a before and after trying to pick out the yellow!!!
Sounds like you need one admirably to the challenge - and also that you may be reverting to your tried, tested and easier ways of achieving a similar effect!!