> For one, all the keyboard shortcuts and commands that you have to learn
> Second, it feels like you have to spend a lot of time to set it all up.
You learn a subset that's relevant to you. Also there is which-key which helps _a lot_.
But, I mean how do you learn, say, Spanish? Do you just drop English and start speaking Spanish to everyone from day one? No, it's something that happens in a dedicated time. Once you feel comfortable enough, and when the chance presents itself, you being integrating it to your daily life.
Similarly with Emacs, you could just start playing with it, maybe say editing your personal scripts with it at times, using Org mode for some notes. And then slowly integrate it to your life.
No matter how much work is done in the UI compartment, a tool as comprehensive and customisable as Emacs will never be learnt in one day. There won't be any magic bullets. It's always like learning a language.
The important consideration is if the returns are worth the investments here. Unlike other editors---which are great software in their own ways, anybody who says "hackers should use Emacs or Vim" or similar BS just don't know what they're saying---, Emacs provides some particular opportunities, which depending on your workflow might not be worth it.
> Third, will it replace an IDE?
Yes, you can get it to do all that. OOTB is hard, but AFAIU projects like Spacemacs and Doom are kinda making that happen.