And within 20 years, how many of those reactors will actually be built? Especially within the Persian Gulf, where nuclear weapons proliferation is a big issue. How many decades did Iran spend under sanctions while building a reactor?

The solution can't be first-world-only, and local solar is a much better bet in equatorial but poor and politically unstable parts of the world.

Unfortunately, nuclear has one big issue in addition to the issues already described (long time to build a plant; geo-political concerns on the link between plants and atomic weapons): when it goes bad, it can go spectacularly wrong. No other power source has produced a singular disaster like Chernobyl where about 2500 square km of land is basically uninhabitable for a few hundred years+. Coal fires are the only thing that come close.

For that reason, the NIMBY forces / politics against nuclear are much stronger than average (both in building the plant and storing the waste). Never mind that, on average, nuclear power is much safer than fossil fuels. People fear the spectacular more than the mundane. Take terrorism vs. car crashes, in the Western world you're more likely to die in a car crash by far, but it's terrorism that stirs up the fears.

As far as global warming is concerned, power generation is only part of the puzzle anyways. Such contributors as transportation and deforestation are also important. Honestly, solar and wind are pretty competitive right now... except for one angle. The main problem with solar / wind / etc. energy generation right now is variability, so the real "moonshot" for this technology is energy storage. (Which is the same real issue with electric transport as well).

And, what might be little known outside of Germany, we still suffer from the Chernobyl incident, as it is still not entirely safe to eat wild mushrooms (and certain game) from southern Germany forests due to radioactive contamination. And that won't change in my lifetime.

Nuclear reactors aren't economical, don't scale well, can't be deployed everywhere and it takes forever to build them.

Even if everyone would agree to convert everything to nuclear reactors now it would probably take a decade before the first goes online and several decades until enough of them are online. That's far too long.

In that same period you can easily get far more energy quicker with decentralized renewables.

Nuclear power have all types of problems for competing on the energy market. From its several sizes available: from incredibly big to absolutely huge, to its bad PR problem and NIMBY, to expensive waste treatment, to any company that runs them getting bankrupt sooner of later.

Solar and wind are are here now. And they get in all form-factors, including single-home sized. Besides, photovoltaics are way behind in the Moore's law, and still have a lot to improve.

Today, pushing nuclear energy is almost guaranteed to get you no result, while solar will probably get you the biggest improvement you can get.