Can I paste a function in the function.php to set this value? Below is how you set it for the WP Rocket plugin. They also do not have an option to set it from the front end..

Users are waiting for the images to load, which is a bad user experience…

function rocket_lazyload_custom_threshold( $threshold ) {
return 100;
}
add_filter( ‘rocket_lazyload_threshold’, ‘rocket_lazyload_custom_threshold’ );