My first job that actually used my EE degree was found by hand delivering resumes in an industrial park. The company that hired me said they never advertised because they either hired someone that an existing employee referred, or someone from another company they met while conducting business. Probably many companies that operate that way, and they would only ever advertise if desperate, and need specific rare experience.
That’s interesting and atypical to my experience. I got caught up in the dot-com bust of 2000 and was out of work for over a year. In addition to responding to advertisements I did a lot of cold calls, thinking that I might strike gold where no one else was mining. Zero luck in that strategy. I ultimately answered an ad that parlayed into a 16 year career (when I retired).