Apparently stellarators only became feasible recently, mostly due to vastly improved computing power, which they need to optimize the crazy shapes (https://www.ipp.mpg.de/w7x gives an idea)
(Heard that on a podcast with two of the lead physicists/engineers working there)
Yes, they are complex and require both, complex calculation and precise manufacturing and 7x is the first one being energy-positive, but tokamaks aren't really ahead either.
(Heard that on a podcast with two of the lead physicists/engineers working there)