Because of modifies a verb. Due to modifies a noun, usually after a form of be. The ACT prefers because of after an action. The delay was due to rain. The test was delayed because of rain. Idioms as a set are in ACT idioms.
After the action, use because of
If you can swap in caused by after a noun, due to can work. If the phrase is explaining why someone did something, use because of. She left due to the noise is the usual miss.
Diction overall is in word choice. Affect versus effect is another cause-and-effect pair, in affect versus effect. Grammar overall is in ACT grammar rules.
The bottom line
Action explained: because of. Noun described as caused by something: due to.
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