The cosmic dark ages: Everything you need to know

Space.com reported, "While it is generally accepted that the cosmic dark ages began 380,000 years after the Big Bang when the first neutral hydrogen atoms formed, exactly when this period ended is still a matter of debate."

Cosmology calculators can show the z number or range here if used.

Example, https://lambda.gsfc.nasa.gov/toolbox/calculators.html

This calculator suggest z ~ 1100 or so when the Universe is only about 370-380,000 years old. At redshift about 6, Universe age close to 1 Gyr. Seems there is a large redshift range where Population III stars and hydrogen gas filling the early Universe with no metals should be visible today. So far, nothing confirmed here it appears.
 
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