For what it's worth, if the keybindings you want are Vim or Emacs-like, you can get this behavior in Bash or Zsh (or probably other terminals) with literally one line of configuration.
I want it to behave like every other text input field on my Mac. So I can do option+left/right to jump words, Cmd+left/right to jump to beginning/end of a line, shift + move cursor to highlight text, Cmd+A to select all, option + forward delete to delete the whole word in front of my cursor, etc
what’s wrong with the standard terminal then?
It does none of the things I mentioned
Option+left/right works, but that's it :-]
The emacs-like keybindings are default for bash (and probably zsh too). So you need zero lines of configuration, just the awareness that they exist.