There are (at the highest level) two kinds recruiters. Those that work for a company filling that company's internal roles, and those that work for a body shop filling the roles of whatever companies agree to pay them a commission.

The former are usually pretty good. They have an idea what the teams need, even if they don't know the specifics of the individual technologies. They usually have very close relationships with the team managers -- especially at smaller companies where there may only be one or two recruiters and a small number of development teams.

The latter are, by and large, worthless if you're looking for a good tech job. They're salespeople who simply aren't incentivized to learn more than the bare minimum about what they're selling. Especially in the current climate most of the folks getting jobs through them are either extremely junior, or can't get jobs anywhere else. By extension, the only companies who have success using them are getting by with extremely junior or extremely bad developers. This is why I, as a developer with ~12 years of experience in back-end development and distributed systems design get an email or LinkedIn message every 2-3 weeks for a junior or mid-level React or Angular job.