Hello,
These are controlled on how you customize the event list or shortcode and how you customize the html for the output. Usually it can be adjusted with your CSS which differs on every theme or on the output you want. You might need to hire a Developer that knows HTML/CSS for it.
I’m also wondering why you would want to display the events as horizontal on mobile? These means that it would be squeezed and chances are it might not be readable. Usually on mobile, especially on small screens, the User Interface is vertical so if can be more readable and a user have a tendency to scroll up/down.
Here a sample link on how to make HTML blocks in horizontal that might help you.
https://www.w3schools.com/howto/howto_css_three_columns.asp
https://codepen.io/Cheesetoast/pen/KFAaq