Millennials are roughly 1980-1998. Gen Z is typically 1998 forward. I’ve seen some say as early as 1996. It’s pretty janky methodology.
Some sociologists use 20 year blocks and other 22 year blocks. In some eyes the boomers ended in ‘60. Others say ‘64.
I was born in ‘60. My siblings as early as ‘54. The difference is night and day. I tend to relate a lot more to Gen X, than Boomers.
They are all generalizations anyway. But the “kids” use the terms without understanding what they mean or the thinking behind the study of Generation from a Sociologist point of view.