Hello,
1) By default, WooCommerce opens first tab when page is loaded. You can try to close it manually right after page loading by adding this code snippet to the Custom JS section in Theme Settings. But this code applied to mobile screens as well as desktop.
setTimeout(function() {
var $tabs = jQuery( '.wc-tabs, ul.tabs' ).first();
$tabs.parent().find('#tab-description').hide();
$tabs.parent().find( '.tab-title-description' ).removeClass('active');
}, 10);
2) Sorry, I can’t provide you a piece of code to display the full amount of tab content and to avoid the scroller. It requires customization and this is beyond our limitations and support policy.
Best Regards.