"Bro" is gender neutral for me. Though I still try to avoid it with transfems I don't know very well (which is... all except one) since I can't know if they'd tell me if it makes then uncomfortable. Since even if you know how it's meant it can still feel bad.
One of the very few things where I'll change how I interact with a transfem vs a ciswoman
"Dude" and "Bro" being gender neutral really varies from social circle to social circle. I always air on the side of caution although I've even seen some cis females call each other dude and bro
Going some 20-25 years back I recall some of my friends from English speaking countries using it as gender neutral, and I guess once I wrapped my head around it, that's how it's been for me.
But your mileage may certainly vary.