Nuclear has a long lead time. Setting aside safety concerns, any realistic shift to accelerating nuclear would not help us much in the 10 year range. If we are most concerned about tipping points, which tbh appear real but impossible to predict, a nearer term but less effective shift to renewables would be warranted.
When I say “realistic” I mean in the current political and cultural climate. If we posit that we can do anything we want, dictator-style, that’s a thought experiment. At which point I’m totally with you: latest designs, aggressive funding and incentives for both r&d and actual projects, etc. That’d complement the progress we’ve made with renewables.