the illusion of mastery
the field is too big for anyone to know all of it.
A lot of people who are actually good at tech work feel like they're bad at it. The field is so big, and changes so fast, that there's always somebody talking confidently about something you don't know, and it's easy to take that as proof you've fallen behind.
VPNs are a good example. Ask most people and a VPN is the thing that makes you safe and private online. The ads say it, the YouTubers say it, and everyone repeats it. Ask a network engineer and you get a shorter list. It encrypts traffic between you and the VPN provider, hides your IP from the sites you visit, and moves your trust from your ISP to a company you probably know nothing about. That's useful. It isn't a force field.
The strange part is what that gap does to the engineer. When everyone around you is that sure about something you know is wrong, you start to wonder if you're the one who missed something. Maybe there's a new protocol. Maybe you're out of date. Years of actual experience lose to an ad read you've heard a hundred times. I think a lot of impostor syndrome in this industry starts right there, with people who know a subject well listening to everyone else sound more sure than they are.
Nobody knows all of it. The people worth learning from tend to be quick to say "I don't know," and then they go find out.
What helps is to keep learning and to talk about it out loud. Ask the dumb question. Explain the part you know to someone who knows a different part. Once people start sharing what they know, it becomes obvious pretty fast that everyone has gaps, and that a few of you together cover far more than any one person could.
So if you feel small next to everything there is to know, that's normal. It says more about how big the field is than it does about you.