I don't think FFTs are particularly good for music visualization if you're trying to be expressive because there isn't a particularly meaningful mapping from an FFT to the subjective experience of music and it adds significant latency. I ended up using a few stacked bandpass filters as well as mixing the raw PCM into the light strip for texture. Compressor with a slow attack and even slower release for auto-leveling (the release has to be like 20 seconds to make sure you don't up the gain a bunch during a breakdown in the music). I ran all the realtime stuff on one core of an ESP32 and a bluetooth stack and all the UI stuff on the other. I was getting about 200FPS on a strip of about 120 SK9822s w/ a custom HDR driver giving me about 11.5 bits of color per channel.
I really miss my bike, watch your shit on caltrain.