We can do all three things at once

I would. ROI takes longer, but they're super fucking profitable as soon as they turn a profit at all. They're generally base loaded 24/7 except for about 3-4 weeks per year for refueling outage. I'm 35, so assume 10 years to build and another 10 years before it starts profiting. I'm retired at 55. Sounds pretty good to me.

Edit: source in response to reply asking for it so they will find it :)

I would. ROI takes longer, but they’re super fucking profitable as soon as they turn a profit at all.
Citation needed.
My state has a pair of nuclear plants built in the 70s, 40+ years ago. Not only are they not profitable, they lose lots of money every year. In 2021, these two plants lost $93 million. source - warning PDF
The only way these two nuclear plants became profitable was when Republicans were bribed by the energy company (First Energy) to force increased rates and fees on the citizens through legislated bail out so the energy companies could make a profit while also gutting the green energy initiatives in the state. I'm not even exaggerating any of this. The former Republican speaker of the house is now in prison serving 20 years accepting something close to (from memory) $150 million in bribes. source
If you can tell me when nuclear power gets cheaper, I'd really like to see it. We certainly haven't here.
- Well, in Germany the government basically paid for all the R&D. Then they massively subsidised the construction. Then the nukes were profitable for a while, especially after they got to run them way past their design life. And finally, the government got stuck with most of the bill for decommissioning. So all in all, nukes are a great way for privatising profits and socialising losses, which is what our current economic system is all about.
  
  That just sounds like a shitty government huffing neoliberal bullshit. Privatizing public services is a terrible idea - just ask AirCanada.
  
  shitty government huffing neoliberal bullshit
  Yeah. That pretty much nails it.
- Source for profitability of nuclear over time
  
  Source for profitability of nuclear over time
  Thank you for sharing your source. I'd prefer a document instead of a 23 minute video, but it is valid for how you arrived at your conclusion.
  However, the source video makes some wildly incorrect assumptions to arrive at nuclear profitability.
  We have the benefit of new reactors coming online in the USA in just the last year, so our numbers are current for real world nuclear plant costs. This would be the Vogtle nuclear power station in Georgia source.
  This example is even more favorable to the argument for nuclear profitability. The plant already existed prior and the recent construction was simply adding additional reactors. So there should be some economies of scale. Here's how that shook out compared to your video:
  
  So your source wildly underestimated the cost and time to build (and likely the interest rate). Keep in mind, they also build reactor Unit 4 at about the same time (coming online about a year later). The cost of Unit 3 and Unit 4 was $35 billion to build and started in 2009. I was generous and only used a single reactor cost as the video's example did for apples-to-apples comparison.
  These factors destroy the argument that new modern nuclear building in the USA is profitable.
  
  Here is an alternative Piped link(s):
  Source for profitability of nuclear over time
  Piped is a privacy-respecting open-source alternative frontend to YouTube.
  I'm open-source; check me out at GitHub.
- Citation needed.
  Watch out, some dickhead might accuse you of sealioning.
  
  Wouldn't be the first time. If someone makes a claim, they can back it up. I do.
The alternative is to be making bank on a far smaller outlay much more quickly with renewables.

Sure would. I put money into renewable stocks and they tanked hard. Looking at you RNW.

We already run carriers and subs on nukes, supertankers and massive cargo ships could use them too. And arguably should, given they're a huge, massive source of pollution.

So why do you think this is not happening? And if your answer is regulations, which regulations exactly would you scrap to make this commercially viable?

I absolutely would and have done so: https://www.vaneck.com/us/en/investments/uranium-nuclear-energy-etf-nlr/

I literally own a bit of stock in the most nuclear-power-related company in my country - so yes.

Yes - it's called my fucking electricity bill.

I wouldn't build a new power plant, but reactivating existing ones makes sense and is cheaper per GW than solar and reactivation has insignificant emissions.

This answer shows that you have no idea of how this stuff works. Reactivating a shut down nuclear plant would require re-certification. Nobody is going to re-certify a plant built on 1960s technology today and for good reason. If you wanted to bring one of those up to modern standards you might as well build a new one.
- Nobody is going to re-certify a plant built on 1960s technology
  Yeah, that's why they're re-starting one built on 1970s technology
  
  It still faces hurdles, including inspections, testing and the blessing of the U.S. Nuclear Regulatory Commission, known as the NRC.
  Yeah, let's see how that goes.

Paper money, sure. But nickels and dimes? No thanks, I don’t want to walk around with radioactive currency