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

Doom Emacs: https://github.com/hlissner/doom-emacs

Doom Emacs themes: https://github.com/hlissner/emacs-doom-themes (can be installed standalone but not sure if they disable the toolbars etc)