This is very good advice. Because OP doesn't talk about how to write emails, here's how to write good cold emails to hiring managers/employees/CEOs: https://interviewing.io/blog/how-to-get-in-the-door-at-top-c...

P.S. I'm CEO of a Series A company. I get a lot of email from prospective candidates. I never hold it against them, and as long as it doesn't look like spam, I reply. Telling people not to send emails (I saw a bunch of that in the comments) is categorically bad advice.