Yeah, I know that the super-flat planar look was the intent, but there's a reason why you don't see much in the real world that resembles the cybertruck. It turns out that the non-planar features of typical car panels are there to add rigidity. Flat sheet metal wants to bend, twist, wave, and even flap in the wind. So there are probably internal supports or struts welded to the panel backsides, in order to keep them flat. Problem is, that process tries to distort the panels due to heat from manufacturing.

And since they opted for stainless, this adds additional problems. In this case: you can't hide imperfections with bondo and paint. The panels have to be perfect, every time. It requires tolerances that belong on a sports car, not a pickup.