AI can be, or will be at one point, developed at home using consumer devices.
If they could do it then countries like Poland or Finland could do that too. They don't, because they have other security guarantees at the moment. If NATO and EU collapsed - the number of nuclear weapons states would definitely increase.
That ignores the sixty years it took North Korea to develop nuclear weapons. It took the US and USSR less time to develop the first nuclear weapons after the discovery of radioactivity in the late 19th century!
The Soviet Union first began training DPRK nuclear scientists back in 1956 [1] and North Korea only managed to finally build nuclear weapons because of assistance from Pakistan with the uranium enrichment process in the late 90s and early 2000s, specifically the design for the centrifuges that fell into Libya's hands [2][3].
[1] https://en.wikipedia.org/wiki/Timeline_of_the_North_Korean_n...
[2] https://en.wikipedia.org/wiki/North_Korea%E2%80%93Pakistan_r...
[3] https://en.wikipedia.org/wiki/Abdul_Qadeer_Khan#North_Korea,...