At least a dozen different socialist ideologies have entirely different answers to that. First you'll need to decide what you consider a state. Some - e.g. anarchists and other libertarian socialists reject the state outright, and don't want anything to replace it. Others reject "only" top down/involuntary authority, or want any replacement to be minimal in scope (e.g. communes).

A defining trait of a national state is sovereignty over a territory and control of the use of violence in that territory, and those are both traits that multiple socialist ideologies explicitly reject.

Whether or not you believe any of the variations can work is orthogonal to the point that socialism is not a singular ideology, but a spectrum of ideologies that where many reject the state, and so the existence of one is not a defining trait of socialism.

Insisting that it is, is a bit like insisting that capitalism is the same as fascism because capitalism too relies on a state (to enforce property rights). If anything, capitalism is inherently tied to the existence of a state because of the need to enforce property rights that many socialist ideologies reject. But very few socialists would equate capitalism with fascism (some would).