If you're not looking for stars with Google on their resumes or 5 year SV experience, which is also OK, there are plenty of engineers who can do a great job without Google on their resumes. Maybe little bit slower, maybe not. If you can't find them, your interview process is broken.
If something doesn't work right, it means you're looking inexpensive talent in expensive areas, or exceptional talent in places where you can't find it. You're remote, but talent often is more about geography.
Also, use GitHub (or git-awards.com) for your search. I have pretty popular repos, in the top 100 JS devs for San Francisco, email is specified in profile, but recruiters don't reach. They just don't use this channel. They only know about one site - LinkedIn.