Hi there, I’ve just set up emacs gui on macos. I am very used to zsh and faced the same issue of not being able to load the correct SHELL env when starting emacs.app from outside a terminal. Since I use a couple of extra env variables and extend $PATH quite a bit in my .zshrc, this was not really acceptable

I am using exec-path-from-shell and have configured it like so in my ~/.emacs:

;; ...
(package-initialize)
(when (memq window-system '(mac ns x))
  (exec-path-from-shell-initialize))
;; ...

You will need to export $PATH from ~/.bash_profile or ~/.zshenv (it did not work from ~/.zshrc, but that’s stated in the docs):

export PATH=/usr/local/bin:/usr/bin:/bin # should be enough for most usages
or
export PATH=/usr/local/bin:$PATH # if you ignore what's in the docs ;)

Finally, no trouble finding erl or any other libraries and programs from emacs gui. I hope you already found a solution or that that helps