Well, after resolving some obvious issues (like “the warhead should execute its firing sequence precisely or nothing will happen”), we enter the realm of highly

Well, after resolving some obvious issues (like “the warhead should execute its firing sequence precisely or nothing will happen”), we enter the realm of highly classified information, and can only speculate how the modern designs would behave (modern nuclear weapons are the product of decades of adversarial evolution, with ABMs, counter-ABM protection, and counter-counter-ABM measures being the focus of research efforts). Like, some designs were “one point unsafe”, but could be this exploited deliberately as counter-ABM protection? Or: we know that there were many efforts to allow nuclear warheads to detonate simultaneously and close to each other (so neutron flux from earlier detonations would not disrupt other devices’ firing sequences), but how exactly it relates to ABM protection? And so on and so on. Exact solutions are classified, and what we can learn from unclassified sources is mostly a speculation.