I think a rule of thumb is "by the time a company is large enough to have someone in tech doing full-time management, your application is going to pass through someone else before getting to them for a second pass of filtering."

Small, scrappy startups will have the decision-maker doing the first-pass filtering. None of those people will be called "manager".

In 25 years, I’ve never randomly spammed applicant tracking systems. My first job was based on an internship and after that I used my network of former coworkers, managers, and local external recruiters.

When you say recruiter, do you mean HR from the company or an external recruiter?

If they already know which company it is, they probably mean an internal recruiter.

When going via external recruiters, you tend to know you're talking to a recruiter before you find out which company the job is with.