Netflix's synopsis for "The Forgotten Battle" describes the movie as taking place "during WWII's crucial Battle of the Scheldt." This was indeed the name of a World War II engagement, which an article on Dutch Review describes as "one of the longest and fiercest battles fought during WWII on Dutch soil," and "considered by some historians to have been waged on the most difficult battlefield of the Second World War."
In that sense, then, the setting and action of "The Forgotten Battle" are rooted directly in history. Its principal characters, however, are fictional, representing different factions in the Battle of the Scheldt rather than functioning as portrayals of real-life individuals who fought in said battle. Dutch soldier Marinus van Staveren (Gijs Blom), for example, is explicitly described as a fictional character on a fan wiki for WWII combatants in film.
Viewers hoping to glean some historical insight from "The Forgotten Battle" can thus learn plenty about the Battle of the Scheldt from the film, provided an understanding that its individual characters never existed.
