i managed to fix it by extending the theme with a custom_dir. so my project set up went to this:

website/
|-docs/
| |-blog/
| |-index.md
|-overrides/
| |-.icons/
|   |-custom/
|     |-twitter.svg
|-mkdocs.yml

then i updated mkdocs.yml to have name and custom_dir underneath the theme:

#...
theme:
  name: material
  custom_dir: overrides
  # everything else

extra:
  social:
    - icon: custom/twitter
      link: https://x.com/

i found these: https://squidfunk.github.io/mkdocs-material/setup/changing-the-logo-and-icons/#logo-icon-bundled and https://squidfunk.github.io/mkdocs-material/customization/#extending-the-theme which helped me solve it