You cannot declare yourself an expert because it’s a relative quality. Only somebody else could define you as an expert because of the problem you have solved for them and with them.
Being an expert is a relative position because there will always be somebody who knows more and better than you and somebody who knows less and worse than you.
At any moment in time, you are always an expert for somebody and a beginner for somebody else.
What to do with your expertise? Ask to whom sees you as an expert and have a dialogue with them. Don’t impose your help. Find, discover, define, and set the problem to see if it is desirable, useful, meaningful, and sustainable to solve that problem, and then offer your expertise to solve it.
It’s paywalled, this is an excerpt of a thread with Achim:
“There will always be people with more expertise than you, there will always be people with less expertise than you, it’s not for you to decide whether you are an expert.”Massimo Curatella
“And it is the job of a knowledge entrepreneur to show up with your particular expertise. So that your audience—people that do get value out of this—can find you”.Achim Rothe
I totally subscribe to the notion of showing up to provide value to be recognized.