Hi,
I want to build a setup which uses 21 5M LED strips with 30 LEDs per meter.
My main question is how to connect all those strips. Do I connect them all to the same pin of a single controller, connect to several pins of the same controller or is it better to use several controller boards?
Does the WLED UDP Sync feature means that if I use several controllers, logically it’s a single strip?
Thanks for your help.
A single GPIO can handle up to 700 pixels if you want decent FPS.
Otherwise a single GPIO can drive all those LEDs.
Be mindful that such amount of pixels requires ESP32.
Thanks for th quick response.
I want to power ~3000 pixels. Can I hook them all to different GPIOs of the same controller or should I use several controllers?
I think I wrote plain enough. 
You can do as you want.
As @blazoncek said, an ESP32 is capable of driving multiple strips (say 5 GPIO’s driving 700 each) if you need effects at good FPS.
The data requirements are pretty well understood and can be handled by WLED.
A more basic issue will be how you power up such a beast.
3150 LED’s at (guessing) .3W each on max Bright White = 945W of worst case power required.
That will take some serious design work to get right and some serious build safety to keep from starting a fire(s)…