I agree, modernized nuclear plants are probably the only technological solution that we have that is mature enough to cut emissions enough within a single decade to prevent irreversible, catastrophic climate change.
My family and I lived for almost 20 years completely off the grid, making our own energy with solar power and using a diesel generator as backup, so I believe in and support renewable energy. It's just not going to be enough, though, especially since world energy consumption is predicted to increase 50% from what it is now, by 2050. Before Covid hit, we were on track to provide almost 20% of our energy from renewables. Sorry, but that's just not enough. It's possible that advances in technology will eventually make renewable energy, i.e., wind and solar, more efficient and, thus, capable of supplying all of our energy needs, but that's not going to happen soon enough to save us from climate change. Rapidly building many, many small, modular nuclear reactors would allow us meet our climate goals. Renewables will not. :(
I feel it important to note here that it's not an either/or between nuclear and renewables. Nuclear, geothermal, wind, solar, and hydro can all be ramped up in parallel.
This "in parallel" approach has some very high powered supporters. Some of them offer concrete reason to believe a renewables-heavy in-parallel approach can do a lot, including have the US do its part to keep global warming down to 1.5 C!
Macarthur Genius grant awardee / physicist / engineer Saul Griffith concludes that the US can decarbonize 80% of the economy by 2035 and 100% by 2050. His analysis was technology-agnostic but determined that the path to achieving this with existing technology is mostly through a huge rampup of renewables, plus expansion of the electric grid, incentivizing of private decisions to switch to electric cars, and similar techniques; the theme is a comprehensive electrification. He thinks nuclear will probably be increased slightly but will still play only a minority role.
His evidence? Griffith compiled, with support from the US government, the largest database detailing US energy usage and generation ever assembled, applied known performance of existing technologies, and analyzed to determine "What does US need to do to play its part in limiting temperature increase to 1.5 C, the goal set by the Paris Accords?" Assuming that we do implement each step at the high end of known existing performance, the path that he says would work would be an intense rampup phase to build infrastructure, followed by wave of private electrification projects.
On the funding side, he reasons that if government's primary investment were to provide loan guarantees, along with rule changes to facilitate infrastructure projects, private funding would finance the bulk of the projects due to the profit motive while the government expense would be about $200/billion year for a decade. Interestingly, the amount of spending he proposes is similar to Biden's proposals, which contain several elements of his plan, but Biden also seeks to invest some funding in R&D.
PS. Once the electrification takes hold, Griffith calculates that the long term cost of the new all-electric system would be cheaper than our current system (about 50% of our current system's cost IIRC). That's on a per-kilowatt or per-joule basis, if I understand him; I don't think he tried to calculate side effects like "if it's cheaper, people might spend more." Apparently it's conceivable the investment would pay off financially as well as ecologically though.
https://www.rewiringamerica.org/145 page handbook (they email it free from this page if you enter an email)
https://www.rewiringamerica.org/handbook