That benchmark is as outdated as completely unrealistic, as if invented by the oil/nuclear industry. Obviously 100% pure solar generation will be completely unfeasable in a place as Germany, but that completely misses the point that a realistic combo of solar/wind/biomass has a FAR higher combined capacity factor than solar alone.
Also, it's based on 2021 (or before) storage cost figures, which have halved in the meantime. https://assets.bbhub.io/professional/sites/44/LCOE-11.png
I call BS.