It's not a simple solution, but a plan for a long-term, robust, self-sustaining world: A good mix of {solar, wind, geothermal, hydro (as storage), biomass, tidal} combined with long-range energy transmission, grid storage, energy efficient buildings, transport, city planning and industrial processes.

Of course let's not close existing plants germany-style while we do it (in the next few decades), but lets not kid ourselves that nuclear fission can power a stable, robust and resilient society that can last thousand of years.

Yes, hopefully we have unicorns in the distant future

Today and the immediate future need solutions that we can already build

All of those options are available to us right now, they are literally being rolled out as we speak. There is a much bigger question about our ability to build nuclear on the scale required.

Honest question, do you know a serious source I can read about how this rollout is being executed? I am only familiar with European energy policy, and grid storage currently is a pipe dream, more efficient construction is very slowly being rolled out and so far doesn't make a dent in the problem, and the renewable mix being expanded is inevitably intermittent (mostly solar and wind, with the rest being negligible), as hydro is a very small component of the mix so far and in the medium term future. The only question about our ability to build nuclear is cost-efficiency and regulations.