Teensy stuff can drive a lot of LEDs, but it's not a professionnal setup except if you get a box for the teensy and properly cable your LEDs, clean soldering etc. Pixelite isn't expansive for the electronics there, you have one fuse on each output, no risk to burn anything if you do bad things with your cables etc.
> is there a direct WIFI LED Pixel Driver with Artnet that works with Madmapper
MadMapper is ArtNet 2-3-4 compatible so, any ArtNet device on the market should be compatible. But I don't know about wifi LED pixel drivers. People generally don't want to rely on ArtNet in installations.