It isn't imaginary. Korea and China prove it is possible to build nuclear reactors for reasonable cost when you don't have endless irrational legal opposition that makes them take much longer to build. What IS imaginary is multi-day grid scale storage. All BES are designed with at most 4 hour capacity.
I didn't handwaved away the study I carefully pointed out how it is systematically biased against nuclear which isn't surprising considering how anti-nuclear the authors are.
Denmark isn't nearly as hard of a case as you think because it has some of the most reliable off shore wind power available.
And it's conclusion about Denmark, if correct, cannot be generalized to the rest of the world. You have to have dispatchable power in an electrical grid and that has to come from gas, coal, or nuclear.