'react-native-render-html' can't change font family for <strong> tag

I'm using react-native-render-html 6.3.4, attempting to use custom font, but can't seem to change the font family for 'strong' and 'em' tags. Other attributes are working like font size or font style but not font family.

        const html = `<p><strong> Custom font bold.</strong> Regular text font family. </p>`;

        <HTML
          source={{ html }}
          systemFonts={systemFonts}
          tagsStyles={{
            strong: {
              fontFamily: 'PLEC-Regular',
              fontStyle: 'italic',
              fontSize: 30,
            },
          }}
        />```