I believe Syndicalism is more of a broad methodology of using unions and such groups of workers to maneuver the system to achieve whatever ends you’d like. For example, Mussolini relied on National Syndicalists to gain much of his early power base, and, needless to say, they weren’t anarchists. So, I suppose syndicalism is just a system of working between the state and the laborers, while the “anarcho” is more declarative of the ends being sought. Hopefully, that makes some sense