Electret Microphone with LM358 gives weird analog reads combined with WS2812

Try a GO/NO GO test where you keep the led code in but do the absolute minimum with it .
Record your results.
Then start with adding the dreaded delays that aren't supposed to be there , starting small and working up , increasing the delay
little by little. Try picking different places in the code and testing it by commenting out all but one location and add locations one by one after incrementing the delay in each location little by little.