A bit late now, but you can set the IDE to compile for any board in the Tools menu without having the board physically connected to the computer.
The quote about FastLED being compatible with any Arduino board is apparently from a time before some of the later boards were introduced, so a test compile and a bit of research before buying any of the more recent boards would be a good idea.
Try the Adafruit_NeoPixel library, do not have a board to test the functionality, but an example sketch compiles without error for the Nano 33 BLE.