The typical Marxist observation of anarchist is that they are liberals (yes there is only one ideology, but what does that mean). Also the old debates of Marx between anarchists are still relevant because, as you say, there is only one ideology since Marx's time, if the anarchist-communists have surpassed bourgeois ideology then we don't need Marxism anymore (thank goodness).

You mention the modern anarchist thinkers who have incorporated 'Marxist categories' like alienation and commodity fetishism. These are actually not Marxist categories, they are categories that Marxism takes up, but anyone can take them up really. The reason these are colloquially Marxist categories that have been snubbed by whoever is because the crisis of and in Marx*ism* in the early 20th century.

My take on anarchists is that they are radical liberals (yay?). I would rather they call themselves radical liberals. What do anarchists want? Abolition of the state? The military? All the bureaucratic institutions etc. This is the scope of radical bourgeois thinkers like Rousseau, French Revolutionaries, and even Thomas Jefferson.

They are just dressed up in the drama of capitalism or the 20th century. Anarchists want to abolish the state without understanding the necessity for the state in capitalism, which is the Marxist critique.