add this

need add this

$date_out .="<style> .entry-meta .entry-date{ display:none !important; } </style>";

before change

function rm_date_css() {
        $date_out .="<style> .entry-footer .posted-on{ display:none !important; } </style>";
        $date_out .="<style> .entry-meta .entry-date{ display:none !important; } </style>";
        $date_out .="<style> .entry-meta .date{ display:none !important; } </style>";
        echo $date_out;
    }

function rm_date_css() {
        $date_out .="<style> .entry-footer .posted-on{ display:none !important; } </style>";
        $date_out .="<style> .entry-meta .posted-on{ display:none !important; } </style>";
        $date_out .="<style> .entry-meta .entry-date{ display:none !important; } </style>";
        $date_out .="<style> .entry-meta .date{ display:none !important; } </style>";
        echo $date_out;
    }

https://ww.wp.xz.cn/plugins/wp-author-date-and-meta-remover/