What makes a plot twist in a whodunit work?

The prupose of the study was to analyse the 2019 movie, "Knives Out," and compare it to my own bachelor movie, "Undercover," to figure out what makes a plot twist in a whodunit work and if I had managed to use what I had learned through studying the Whodunit genre and apply it effectivly. This was done by first definging the genre itself, and its relevant terms. Then by looking at the most important traits of whodunits in both Knives out and Undercover to both compare and understand better how they solved the story. I have learned through the research and analysis of Knives Out that it makes use of all the formulaic traits most characteristic to classic whodunits in a way that is effective and ties up the arcs that it sets up. These were mainly the use of a large cast of characters with diverse personalities for entertainment but also misdirection and red herrings that helped pace out the timing of each reveal until the final main climatic reveal of the culprit.