Is there a way to run Emacs on MacOS with an updated interface? Running Emacs in the terminal limits the functionality, but the GUI versions I've tried are garish-looking to me.
By garish-looking do you mean with the default white background and awful looking buttons?
I installed the Doom Emacs configuration and it looks really great and modern on macOS. I think you'd like it! Definitely worth a quick install to see what is possible - you can always go and make your own configuration based on that if you want
I used a few packages to get me there (though some of it can be done through configuration, it was just easier that way). The relevant bits in my config are:
On a similar note, I have found on Linux that just switching to a virtual terminal and running Emacs in text mode is an absolutely wonderful way of achieving deep focus without distractions. Obviously not much use if you need a web browser on your second monitor though.