Which is why if you're job searching you should spend a decent chunk of your time making connections. Go to meetups, work on open source, volunteer, join a hackathon if such a thing still exists near you as well as "job board" job searching.
I read the evergreen "What Color is Your Parachute" when I was 18 or so (before the web), and it profoundly affected my take on job search (and sales). It gets updated pretty regularly though the original author has passed not that long ago.
23 years in and all my (contract) work comes from my network. Parent comment is the advice you need.
It's never too late to start, but it is hard to do on demand. Also the way you behave within a company will follow you. If you're NotAnAsshole™, can do the job and I've worked with you I'll help you get your next job for the rest of your career.
Don't work on open source if you're just trying to pump up your resume. Contribute only to projects you use and can make actually valuable contributions to. It does look good on a resume but telling people to do it because it looks good on a resume hurts the open source community imo.
I read the evergreen "What Color is Your Parachute" when I was 18 or so (before the web), and it profoundly affected my take on job search (and sales). It gets updated pretty regularly though the original author has passed not that long ago.