You can easily change the font size from the element settings.
Please edit the Information Box Carousel widget, then go to the Style tab. In the Title typography section, you can adjust the font size as per your requirement.
Can I have the mobile version display without borders and the desktop version with borders? Because on mobile, the icons become very small with borders.
To hide the border around the image in only on mobile, please use the below custom CSS code and paste it to Theme Settings > Custom CSS > Mobile CSS section: