The state will cease to be when class does as the state is simply the instrument of class rule.
When the state ceases to be the government remains as administration and coordination is necessary for modern production.
When the state ceases to be and socialism has reached its end goal that is called communism and is impossible in one country as the antagonism between the proletariat and international bourgeoisie remain. Then so does class society.
I’m not holding my breath to wait for global communism before I see a movement toward class abolition within any country.
So you’re not interested in reality. Communism and class abolition are only possible globally whether you hold your breath or not.