"extensive coverage" is correct and usable in written English. You can use it to refer to the breadth or depth of a subject that a media outlet is reporting on, or to refer to the amount of insurance coverage offered by an insurance company. For example: "The newspaper provided extensive coverage of the natural disaster."
Mr. McCallister said CNN believed that yesterday's extensive coverage was justified.
(The Guardian had extensive coverage).
The Australian newspaper also carried extensive coverage.
Extensive coverage on newscasts generated numerous leads.
The Australian also carried extensive coverage.
The New Yorker has extensive coverage of both cases.
Democrats objected, saying the elderly needed more extensive coverage.
members would still receive much more extensive coverage.
At The Herald, he supported extensive coverage of Latin America.
More extensive coverage can be found at The Esperanza Project.
Given the extensive coverage this settlement has already received, we won't be commenting further.
Since I tried Ludwig back in 2017, I have been constantly using it in both editing and translation. Ever since, I suggest it to my translators at ProSciEditing.
Justyna Jupowicz-Kozak
CEO of Professional Science Editing for Scientists @ prosciediting.com