How to disable on mobile?

Hello!
Unfortunately there is no option to disable gallery on some devices, but you can disable it using css code.
Just add this code to your theme style.css file, you can use theme editor in WordPress admin menu https://prntscr.com/9vzud2 or use FTP and any text editor to edit this file.
Put this css to the end of style.css file –

@media (max-width: 320px) {
.grid-gallery {
display: none;
}
}

where 320px – it is the width (the same or smaller) of device screen for which you want to hide gallery on your site.

Please try it. If you will have any problems with it – just let me know!