The steps in this guide enabled me to avoid using any CDNs and shrink my bulma CSS to just 19 KB. It also shrinks BulmaJS from 100+ Kb to ~20 Kb with a custom fork of BulmaJS that only builds the navbar, file, and dropdown components.
First, we have to create a subtheme of drulma.
Next, we override the drulma libraries.
Add the following lines to mydrulmasubtheme.info.yml: