I wrote a blog post about the problems of using the phrase "hey guys", as it is not a gender-neutral expression. I know many people use it and never stopped thinking about the meaning and aren't using it to exclude anyone. If you're one of them, I hope this blog post helps you understand some aspects of the problematic nature of the phrase.

https://eevis.codes/blog/2021-07-24/why-im-not-one-of-the-guys/