The Melania documentary is an important artifact that historians will be talking about for decades, although not in the way those involved anticipated.
Wikipedia says it "had the highest opening for a non-concert documentary since the $10.7 million opening for Chimpanzee (2012)".
It did well by documentary standards, poorly compared to its budget, and the stories about empty theaters are mostly in areas with very weak Trump support. Those stories spread mainly because they makes us feel good.