Trying not to fry another Nano

Here's what I'll try then:

  • Feed the leds with 5 v only (no connection to Arduino power). The leds does not need to be connected to power through the Arduino as I understand it now? They can be fed separately as long as the data comes from the Arduino.

  • Get a proper original Arduino this time.

  • Perhaps I could try to limit the power consumption as pointed out I am potentially underpowered if I run all the leds at maximum white.

Is there a way to physically limit the maximum output (Ampere) or should I do that in the software, I could limit the maximum dim level.