That should be your job. Even the "tedious" parts are too important to be left to a non technical person. Time of day for scheduling interviews really does matter and the initial communication of scheduling this can tell you an enormous amount about the candidate.

Your job should also include lots of time on LinkedIn searching, as many HMs do today. Letting a recruiter do this for you will give you many more bad interviews (expensive) than you'd get otherwise.

But apparently "tedious work" is above a HM. Have fun being on conference calls all day, pretending that you and not the engineers are the ones who do the work. Worker self management needs to become more of a thing in this field in general if we can't trust HMs to take an active role in candidate selection. Companies that disvow managers and empower their employees produce far more excellent work (e.g. valve) even if they don't always do it on the schedule that execs want - so this would be a net positive for the industry.