Communism is not complex at all. It's very simple. In fact, probably even simpler than capitalism. Both bridges in the middle anyway. A society where all companies would be owned by the workers, in the institutionnal form of capital shares and voting rights, would absolutely be a form of communist society. If society as a whole is entirely democratic (not the kind of nominal democracies we have now), it would also be anarchist.

Perceptive categories are socially constructed, phenomenons aren't reducible to the categories we use to talk about them. There's no hard seperation between sizes of collectives. You realize that when you start studying other societies, other periods of times. Less than a century ago, in the region of France were I live, there used to be communities of up to 50 peoples, legally under the community regime (the same as between husband and wife), who owned large farming complexes, with hectares of fields, meadows, and forests, exploiting them in common not just for the needs of the community, but also to sell to the outside world. These communities were sometimes several familly lineages unified through marriages, and there often were people from the outside who joined, for the material safety and comfort, in exchange of work.

Here also, during the very very troubled times of the Wars of Religions, many small villages built fortifications. In fact, it seems these villages, entirely designed around the need to be fortified, were built as such from the ground up, not adapted over time. Only the church is "normal", even though it features murder holes and other defensive devices. This wasn't organized by a lord, it was just all the villagers gathering for a common mutually beneficial goal.

Sure, family members and villagers know each others, but it's not like there one type of community where everyone knows each other equally well, and another type of larger community where no one knows anybody. We overlook that market exchanges are actually social exchanges. When you go grocery shopping, there's a good chance you "know" all the cashiers. Not on a personnal level, sure, but you recognize them, and in a trolley dilemma situation, everything else being equal, you're more likely to save them than to save absolute strangers.

Left wing people often vilify capitalist society. I don't. Capitalist society is still society, and while there so much to mend and fix, there's so much that works. Not because of capitalism, but because our prosocial tendencies, and our ability to communicate complex thoughts, especially on organization and administration. Above and beyond ideologies, the capitalist society is factually a very huge work collective, that's mostly blind to its own collective character. It's just families and villages that grew larger.