Touching up the Tag Cloud

You can change how the tag cloud displays by adjusting / adding various parameters. See https://codex.www.ads-software.com/Function_Reference/wp_tag_cloud

try to use a filter in functions.php of your child theme:

example:

add_filter('widget_tag_cloud_args','gametilldawn_change_cloud_args');
function gametilldawn_change_cloud_args($args) {
$args = array('number'    => 30, 'largest'    => 25);
return $args;
}

check the link posted by @premiumwp for possible arguments.