Yes. There are almost too many ways to customize Quarto. The gallery has some examples. YAML settings are abundant and it's possible to mix in all sorts of CSS and JavaScript.
You can also replace the all Pandoc's template using the correct argument (Quarto - HTML Options). This could have side effect though if you template does not evolve with future quarto version.
Also, Paged.js support will come in a future version. This will allow to create some better template for paginated document using HTML and CSS. Useful for report and other company document. Example of what can be done with the R Markdown package today: GitHub - rstudio/pagedown: Paginate the HTML Output of R Markdown with CSS for Print
Without going to the length of creating a format, you can extend the default template using includes (Quarto - HTML Basics)