If they were easy to build, European car companies would have no problem to build them.
Of course, putting a battery and an electric drive into a car is simple. Electric cars are 50 years older than combustion cars. But there’s a reason why they did not took off in the 1840s and why we did not use electric cars for 180 years — building usable ones is difficult.
They’re easier to build than internal combustion engine cars. But that doesn’t mean they’re easy to build in general.