The phrase "amazingly complex" is correct and usable in written English.
You can use it to describe something that is intricate or difficult to understand, often in a positive or impressive context.
Example: "The design of the new software is amazingly complex, showcasing the advanced technology behind it."
Alternatives: "incredibly intricate" or "remarkably complicated".
Notes on the cassette box call the film "amazingly complex".
Thus this show traces an amazingly complex map of influence.
A 747 is amazingly complex, with multiple backup systems.
"In fact, the stories these people told about these images were amazingly complex".
It's an amazingly complex place, in terms of both culture and landscape.
This is not at all to diminish the amazingly complex behaviors exhibited in nature.
Interactions and signal transductions between immune and non-immune tissue components (e.g., cells, organelles, proteins/enzymes, lipids, neurons, DNA/RNA) are amazingly successful complexes of turnover and regeneration processes with durations lasting from a fraction of seconds to several minutes; few days or months and even years.
The next three centuries witnessed an amazingly rich and complex American Jewish history: an encounter that would forever invest new meaning in the adjectives Jewish and American.
It is, however, quite funny, or at least witty, as a result of Musil's amazingly specific and complex figurative language.
Its director is also its protagonist, a young man who worries that he is oversimplifying the beauty of the woman he loves — and who makes an amazingly and delightfully complex film to say so.
"Third Church is a rare Modernist church in the city," Mr. Maloney said, "and the complex possesses amazingly high integrity (in all respects: location, design, setting, materials, workmanship, feeling and association), down to the original carpeting and seat upholstery in the church auditorium".
