I'd be curious if the design of the Cybertruck affects readings at all. It's got angles straight outta an F-117.
I reckon it's probably not that bad, there are big surfaces that are almost normal to what would be incoming radio energy. Stealth shapes tend to reflect energy in a completely different direction from the source.
Here's the closest thing to data I've been able to find. I have no idea what to do with this info.
The polar plot at the end would be useful if there were plots for other cars and trucks to compare to. I'm assuming that it's a simulation?
I think "stealth" planes assumes the radar is under the plane on the ground? For the geometry. And they have some color or alloy that reflect less.
It's cooler than that these days - under the paint are antennas plated? printed? onto the skin panels that are tuned to absorb specific frequencies of interest.