Hello,
Font sizes and line height styles are transformed using all conversion plugins. On https://www.phpdocx.com/documentation/conversion-plugin/preparing-the-templates-for-its-conversion (Supported OOXML tags and attributes when using the native method section) you can read the supported contents and styles when transforming DOCX to PDF using the native conversion plugin and how they are converted.
Regarding font families, please check the information available on Good practices when working with font families (Fonts in the conversion plugin and Fonts in the conversion plugin, native method sections). Using DOMPDF as the conversion plugin you need to include the fonts. Using LibreOffice as the conversion plugin, the fonts must be installed in the OS or embedded in the document.
Regards.