The usual con to get to the conclusion you reached is to assume batteries are used to get to 100% renewables. But batteries are terrible for long term storage and rare event backup, so this is just bad engineering. Batteries + hydrogen does much better in most places, especially at high latitude.
And hydrogen comes with it's own challenges, as a large % of energy is lost in the conversion to and from. This multiplies how much solar you need appreciably. There is no easy solution here, many hard ones. We can do it but need to be willing to do that hard/expensive work.
Yes, hydrogen comes with its own challenges, but batteries and hydrogen are synergistic. Each covers the weak point of the other. Most of the energy stored goes through batteries (efficiency), while most of the energy storage capacity is in hydrogen (capital cost). So the system ends up being cheaper. You do not actually increase the needed generation all that much, because most of the stored energy is still going through batteries, not hydrogen. And in particular, unlike the only-battery solution you don't need to ludicrously use batteries for seasonal energy storage or rare event backup.
Most of the hydrogen produced would, anyway, be used immediately in industry, excepting only when the storage tanks need topping off. The electrolyzers would never, ever be idle.
We need the hydrogen regardless, so its usefulness to store surplus energy besides is a bonus.
