The Legendary Dragon Alephwyr, named Alephwyr, BA

You would actually have means to stop it in a collective and non-profit orientated society. The world is no longer in control of oligarchs, but in the control of common people.

Ok, you focus on that then and I will continue to immiserate myself as everyone intelligent ignores the technical requirements of a technical based solution because I am the one talking about them

Mate, you literally need a socially guided techno-production for you to have a platform to universalize any solution. You can't simply focus on a piece of the puzzle, a sword isn't any good without someone to swing it

Literally program robots to auto nuke everything that doesn't conform to spec

The spec is determined by a programmer. And additionally you said you were about maximizing welfare, property rights are often antithetical to that as people can hoard goods and distribute them to cause mass suffering. So you now have a robot maintaining fascism forever

Special case. Won't matter in post human post scarcity context anyway

You will literally require a specific trend in society to get a utopia like that, dreams of computers coming alive and solving anything are bs and misinterpretations of actually interesting ideas about AI ala Nick Land

These things simply won't happen on their own, you are simply content to role the dice on this and as a result you're guaranteed to end up with techno hell, and you might even end up in it