Well there was a reason I remembered it as a prequel.
A Quiet Place 2 Is Both a Prequel and a Sequel
As reported by Collider, Krasinski was hesitant to commit to making a sequel. However, with his wife and co-star Emily Blunt and Paramount's support, he found the way to make it work thanks to Blunt's idea to view the film as "not a sequel," but more of a "second book in a series":
"It was actually Emily, of course, who articulated it better than me. She said the same thing, it was like, ‘No way, don’t do a second one,’ and then I pitched her my idea and she was like, ‘So you’re definitely doing that.’ She said, ‘But it’s not a sequel. It’s the second book in a series,’ she said, ‘It sounds [like] semantics but it’s true, it really is—you’re not doing anything that’s like, alright I’m gonna take all the things you love and just kinda repeat them but in a different way.’ It’s not A Quieter Place, it’s sort of an exploration of getting to live in the circumstances, and that’s really fun.”
"These ideas appear to have become reality as A Quiet Place: Part II will continue the story from the original, but also give more context into the world that is forced to stay quiet."
A Quiet Place: Part II appears to be more of a prequel and a sequel to 2018's A Quiet Place, showing the events of "Day 1" of the alien invasion and those following the original.
www.ign.com