In summary, to anti-capitalists the question is not only how to have an economy without authoritarianism, but also how to rework the very concept of labour, how it is thought of, practised, etc.
What is it about labour in class societies, they ask, which means that it can only be seen as something which needs to be compelled, either by holding the means of survival (a wage) over the worker's head, or by placing them in a state-industry job for labour tokens? Both the capitalist and 'socialist' solutions are authoritarian. Why?
Unfortunately a lot of the popular discourse around Marx's actual works has been obscured or discounted. Yet it is impossible to validate the USSR, Cuba, China, etc. as 'Marxist' or not without knowing what he wrote himself. It's just as rare to find a leftist who's read Marx as it is to find a right-libertarian who's read Marx.
Actually being that right on their own would be difficult for the same reasons it would for a command economy period, and proving it enough to gain followers would be difficult but it would be possible.
Give a reliable "crystal ball" and predictions always being clear and right where those that obey see outcomes accordingly the sensible would start to follow the commands without any force behind it. There is no need to use force to punish jumping off of a cliff essentially.
It implies the reason it depends upon authoritarianism is because as a model it cannot compete.
Anti-mask-wearers and anti-vaccinators have conclusively shown that this cannot happen in practise.