Hello,

Add below Custom CSS code to Theme Settings > Custom CSS > Global custom CSS to control the width of the banner.

.header-banner-display .header-banner {
    max-width: 120% !important;
} 

Your header banner text is long and it does not fit in one line. You need to reduce the font size in mobile devices to fit it in one line.

But Alternately, Try to create HTML blocks and use the marquee widget in the page builder and add the text.
https://ibb.co/2Mdwpm9

Then Go to Theme Settings > General > Header banner and use this HTML Block in the banner content.
Screenshot for clarification:
https://ibb.co/NSx4rMt

Hope this Helps!

Best Regards.