As a one time IELTS examiner, I should know this, but...
"Complex" doesn't mean complicated. It means a sentence with more than one clause. Right?
How many types of clause exist in English?
There's the dependent clause, the relative clause, and the conditional clause. There are gerunds. There are independent clauses compounded.
And this post contains... one complex sentence? Arguably, the first sentence is technically compound. The others are all "simple"?
(☍﹏⁰)