Nuclear is the worst possible option to fill said gaps. Nuclear reactor need to run at a mostly stable output permanently, they are slow to react to changes and can’t be switched on or off at will.
You could use them to generate a stable base power level, but that’s the opposite of what we need. It wouldn’t change anything regarding the need of energy storage.
The best option currently as a gap filler is gas cause it can be turned on or off in minutes when needed.
Not keeping up with demand is a self-made problem. Multiple EU countries already have multiple days a year where they use 100% renewables.
That has nothing to do with age. Most people nowadays are so used to instant gratification that they struggle with stuff that only helps them in the long term, me included. Last time I tried to seriously sit down and learn I caught myself doing dishes and watering plants after not even 30mins.