More wind capacity wouldn’t solve these issues. They arise specifically when it is cold, dark and windless across Europe, due to a lack of dispatchable electricity production in Germany. Germany instead imports electricity from its neighbors, and Sweden (due to EU regulations) has to export. This in turn drives prices through the roof for Swedish consumers, despite a de facto electricity surplus.
Which in turn would require enormous amounts of excess generation capacity and transmission lines.
Beyond a certain point it’s simply more efficient to install dispatchable electricity generation.
Oh and as for your last statement it is simply incorrect. Nuclear power plants are the single most reliable electricity producer. https://www.energy.gov/ne/articles/nuclear-power-most-reliable-energy-source-and-its-not-even-close