Some people have irrational exuberance around nuclear technologies, and the numbers in that overly long explanation are an example of that. $5B for 1GW of nuclear?! HAH!
There's a systematic bias among all energy professionals to both vastly underestimate the cost of building nuclear, and overestimate the cost of solar, wind, and storage.
Go back 5 or 10 years, look at the numbers projected, and it's just wild. I've never seen any other industry where there's such a mass hallucination among people that otherwise consider themselves "serious people."
Look at LFSCOE instead of LCOE. The electric grid can absorb a bit of intermittency relatively cheaply, but then you need to account for the system costs.