So here in the U.S., we encounter an issue in building socialism that our European and Asian comrades don't necessarily have. Namely that the labor movement has been safely kept from actual political power (namely forming anything even resembling a labor party) by the established government, that "communism" is more associated with foreign movements and a "fad" adopted by coastal elite liberals than a legitimate proletarian movement, and our rapidly slipping position as global hegemon allowed the previous generation of workers to see both a large increase in their standard of living as well as comfortable wages leaving communism to the kind of people who would engage in radical politics in times of prosperity: alienated youths and social recluses.
Overall, the mere act of building a cohesive communist movement in America is stymied by these myriad factors all playing off each other: if a communist party is formed it isn't expected to achieve or do anything, if it grows large enough it'll be split by bored coastal suburbanites adopting one strange tendency or another to LARP as being "deep political thinkers" or engage in spectacle politics, finally those making up the movement, initially, would be the kind of people who can afford to dedicate such a large portion of their life to politics so isolated from the common working man that it can hardly be argued that they represent the interest of the proletariat.
Thus, it appears to me that there's only one way to properly organize a leftist movement that doesn't fall into the trap of the three prior points I mentioned: radical unionism. Being elected doesn't matter, because votes alone are just the illusion of power.
Labor, however, is power. Even a small union in a big city can do more to affect policy and economics, than a large party operating only in the electoral sphere. You cannot commodify unionism, as unions are diametrically opposed to the Capitalist class and so advertisement of any workers organization, even if it's "tamed" unions collaborating with the bourgeoisie, would be cancerous on Capitalism's growth. Finally you crack down on woke-takes from IdPol types, after all it's easy for some bougie fuck to claim some "oppressed nationality" and then silence criticism by claiming you committed some terrible (race, sex, etc)-ism against them, or that so and so socialist party is terrible and should be boycotted because they don't cater to their bourgeois idpol tendencies enough, yet when factoring in the union element you wall these people off. They hide among the universalism of Marxism, of this abstract notion of "the people" to claim that since it's for "the people" then it should create a welcoming environment for "all people", thus allowing their liberal wrecking to commence under the guise of making things more "welcoming" for one abstract and superficial group or another. But unions are rooted firmly in the real world, in the real work place and at the real intersection of politics.
How can a bougie journalist condemn a group of coal miners or retail workers for their "intolerance" when they're not a real part of the union, when they don't even work in the same trade? Unions are not passing fads to join like a political party is, but a real commitment that roots you to a group and a work place. It's made up of real people, who at least are part of the workplace and the working class and are "normal" folks trying to make a decent living instead of political-obsessed weirdos.
Thus, in the U.S. at least, adopting a syndicalist line would probably be better for the growth of a real worker's movement than trying to grow a specific tendency in Marxism.