Oh I just sperged out an answer.

I'm a millenial myself and listened to em since my teens, but for some reason, I've always associated GenX to The Offspring.

Something about the energy and themes in their music was very much GenX energy to me. Like it didn't quite come out of my own generation, but was rebelling against aspects and culture of my parents' (boomer) generation.

I didn't do a deep dive or anything recently so not sure how accurate my impression was