Yes, your proposal would have been an acceptable approach in 1990. Instead, we have been happily increasing our CO₂ emissions every year since then*. No, we no longer want diversity in the power grid; "reasonable" solutions don't move the needle. Even if the entire world would go carbon zero overnight, the global temperature would continue to rise for decades before settling around a new steady state. It's not a matter of holding out a bit longer for tomorrow's magical solution: every piece of fossil fuel burned today makes the planet more unlivable tomorrow.

We are currently on track to reach the "climate-compatible" scenario of the Paris accords (+1.5°C climate increase by 2100) in 2030. We will exceed the "minor change" scenario (+2°C) in 2050. Those targets are already locked in, they are unavoidable because of the delay between CO₂ emissions and their full effect. Maintaining our current levels of emissions gets us to 3.5°C above historic averages in 2100, which is the lower end of the disaster scenario in the Paris accords.

https://royalsociety.org/news-resources/projects/climate-cha...

* except for a short drop in 2020 due to Covid. You may not like it, but that is what full climate change mitigation looks like today because we didn't act sooner.