“A guy by the name of Darby conjured it up using vague references in the NT.” That is simply and demonstrably false.
John Nelson Darby (18 November 1800 – 29 April 1882) was an Anglo-Irish Bible teacher, one of the influential figures among the original Plymouth Brethren and the founder of the Exclusive Brethren. He is considered to be the father of modern Dispensationalism and Futurism ("the Rapture" in the English vernacular). Pre-tribulation rapture theology was popularized extensively in the 1830s by John Nelson Darby and the Plymouth Brethren,[1] and further popularized in the United States in the early 20th century by the wide circulation of the Scofield Reference Bible.