"In the missile silos it says in 21 earth got destroyed by a nuclear exchange but the technology still existed in universe'' shouldnt level 1 missile silos be able to make nuclear missiles and level 2 nuclear thermo-nuclear missile as well

Okay, but what would they do?

what they would do is add a new weapon to the game see some parts of descriptions of buildings are loose in the sense they say things not in the game such as nuclear weapons theyed destroy buildings

Well then I say no. Buildings shouldn't be able to be destroyed.