There's a need for "base load". I hesitate to use that term because people get carried away with weird notions of it. If you slap a percentage on it, it's probably closer to 5% than to 50% of overall capacity if you look at it at a European level. We're talking a cloudy, wind free day across the entirety of the continent. A day would be tolerable. A few weeks highly unusual.
The thing is, that base load is much smaller than the current base load provided by nuclear + legacy fossil fuel plants. Germany has been shutting them down by the GW. Nuclear is nearly done. Coal is next unless they have to get out of Russian gas first. They're putting 200 billion into fixing their grid in the next few years. Something, tells me that they'll manage without blackouts. Blackouts have not been a problem so far when they grew renewables from next to nothing to the majority of their supply. Same for other countries across Europe.
A little bit of nuclear on the side will help. But it will mainly keep energy cost high because all that stuff has to be subsidized. Maybe these smaller reactors will reduce prices to be a bit less problematic. Otherwise, expect renewables to outgrow this stuff by orders of magnitude like it has for this exact reason. Add a few GW of nuclear over ten years or so. Add a few hundred GW of wind. Just wind. It might add up to 5%. That might be enough. I'm not against it. Just realistic about prices and amounts.