I linked you to a comprehensive study that explicitly discussed overbuild and storage to meet both diurnal and seasonal variation, for 147 regions around the globe.

There are many interesting take aways from that, but the one you quoted, and added your own emphasis to, is that solar has a 25% capacity factor.

> Because the sun is only shining for part of the day, solar panels can on average over the whole day produce energy at maximum of around 25% of their installed capacity"

Why did you find this interesting if you are aware that the sun doesn't shine constantly all day and night?