E-E-A-T is not a direct ranking score, but if you ignore it in competitive niches, your site will not survive.
It is definitely not just a buzzword. If you are touching YMYL (Your Money or Your Life) topics, Google will crush you without it. I have had to do full site audits and completely delete YMYL articles, hitting them with 410 status codes, just to save the rest of the domain because the trust signals were not strong enough.
Slapping a fake author box on your WordPress posts does nothing. If you actually want to build trust that moves the needle:
Nail your schema. Use proper JSON-LD Organization and Author schema. Search engines need to connect the dots and see you as a distinct, real business entity, not a ghost.
Real off page signals. You need actual brand mentions and links from relevant sites in your specific industry. Cheap bulk links will never build trust.
It takes time and costs real money to establish. But building actual credibility is exactly what protects your site from getting wiped out during the next core update.