Hopefully simply the button has gone bad. Maybe someone will chime who knows better what else to try/test.
I assume would need to remove button, figure out what type of switch it is, buy an aftermarket (ie non-OEM) replacement, wire / splice it in, and see if it properly controls the lights.
If no change then I'm thinking the control box for these add-on accent lights has developed a fault.
On a 2015 or 2016 at a junk yard that I removed the center console from, the control box was attached (glued) to the underside of the armrest storage bin (inside the center console).
If the same with your car then could try going in through the center console rear panel, otherwise looking at removing the entire center console in order to gain access to it - to repair or replace with a new one.
In my case some of the wiring plugged into the control box via connectors, but I don't recall if all the wires did (ie. some may have been hard-wired).
Wiring in a new button switch might not be too big of a deal, but if have to go beyond that then if me I'd call it a day and just try to be happy / grateful for the one color still have. Afterall it's partially still working