No it isn't. And to a Studio such as Disney only the film Anthology is relevant and Alien, Aliens and Alien³ is a complete story, Alien Resurrection is self contained.
And for new popular entries? Isolation is also self-contained, as is The Cold Forge and the OG AVP comic.
The Prequel series is the only one to explicitly end on an unfinished note, as a Trilogy often does.