It's certainly possible to learn lots of useful things from language teachers.
However, as you already know, learning "about" the language simply isn't enough.
What I can offer you is something other people can't. It's the real-life experience that comes with learning to speak 7 foreign languages fluently. I don't just write about language learning... I actually do it, and there are plenty of videos on YouTube to prove it.
But there's more. Not only do I have the practical experience of learning languages, I've worked with countless people to help them learn too. Thanks to this, I understand very well the specific problems that hold people back. Things like...
1. Confusion over how to study
2. Problems in studying regularly
3. Not knowing how to start speaking with native speakers
4. Loss of motivation when it all gets too overwhelming.
I understand these problems and I know how to deal with them.