I know a guy

My man = You did good.

My guy = That could have gone better.

My brother in Christ = What the fuck have you done?

Isn't it "gal"? As in guys and gals?

It depends on usage.

"He's a guy." Is gendered.

"Hey you guys!" Is gender neutral.

"She's a guy." Is transphobic.

I think there's never going to be a true consensus on things like this.

A friend who is a trans woman told me that sometimes when people say "hey guys" or similar, she often feels an instinctive rush of dysphoria (especially if it's a context where she's the only woman in the group), but that she realises it is often intended in a gender neutral manner, so it's not reasonable for her to feel upset at this. She considers the upset that she feels at this to be "her problem" so to speak, and doesn't expect people to change how they speak. Since this discussion though, I have tried to be more mindful of it when using words like "dude" or "guy" as collective terms.

I've started using folks because I couldn't answer that question

I’m not your man, sir.