org-bullets VS org-superstar-mode

I use the Modus Vivendi theme, FiraCode as my font, and org-bullets for styling. My headings are easily distinguishable across the levels in this set-up.

That's normal. The fancy dots come from the package Org-bullets. Different sized headings are usually theme dependent, I'm not sure off the top of my head which of the doom themes support them though. As for the built in themes, I know that the Leuvan theme supports them, and the Modus themes do as well. It's also very possible there is a variable which dictates the behavior of the org headings. I would use the built in help to search for a variable with a name along the lines of org headings or org height, something like that. You can access the help with M-x describe-variable or with the regular emacs keybindings (sorry I'm not an evil user) C-h v

You probably want something like this:https://github.com/sabof/org-bullets

According to the org-superstar-mode homepage, I added the following to my .emacs-use-package.org file, which is called at the very end of my .emacs.el file, after the call to custom-set-variables:

The org layer in spacemacs comes with https://github.com/integral-dw/org-superstar-mode enabled, if I read the documentation correctly.

org-superstar-mode can prettify headline and plain list bullets. But according to its README it (I guess org-mode itself) doesn't really have a concept of levels for plain lists, so it only prettifies the different bullet characters.

Link to git repo

org-superstar-mode or org-bullets