My recommendation: lower your expectations about who you'll be
Not in a sad way. But if you're about to become a dad, stop trying to be the cool guy who has it all figured out. Just accept now that you'll probably be tired, smell like kid stuff half the time, and say things like 'did you poop?' to a small human. Embrace it early and you'll be way happier than if you fight it.
Needed to hear this before baby number 2 arrives in a few months. I've been dreading losing myself and you just made me realize that's actually the whole point.