Need to show 7 posts from actual date

Try this

static function loop_args($parent_id, $number) {
    $today = getdate();
    $args = [
        'cat' => $parent_id,
        'showposts' => '7',
        'orderby' => 'ID',
        'order' => 'asc',
        'date_query' => array(
            array(
                'year'          => $today["year"],
                'month'         => $today["mon"],
                'day'           => $today["mday"],
            ),
        ),
    ];

    return $args;
}