A wonderful QoL feature that was missing in BF1 is finally back! Thanks (I assume) u/_jjju_ for this! You can now step through the individual RGB values with the D-Pad (or equivalent) allowing us to pick specific colours, instead of having to get "close enough" with the picker tool.
Note that these are not the default Firestorm colours, I changed mine to match the normal self/squad/team/enemy colour palette of BFV.