List on Desktop, Grid on Mobile

awideman (@awideman) was on this list asking about how to accomplish this. Others too but no answer was given.
Change your option in Customiser to ‘List’ and then add the following to functions.php:

add_action( 'woocommerce_after_shop_loop', 'kvf_shop_loop_list_init' );

function kvf_shop_loop_list_init() {
	if ( wp_is_mobile () ) {
    ?>
	
<script type="text/javascript">
    jQuery( "ul.products" ).addClass( jQuery.cookie( "gridcookie" ) || "grid" );
</script>

<?php
	}
}

Hope this helps.