Customized permalink variable on single publish

I am making an attempt rewrite url for permalink on single publish
my permalink: /%postname%/
My single kind: http://instance.com/abc-def/?chapter=1
adc-def imply: %postname%

i need permalink is: http://instance.com/abc-def/chapter/1
However it’s not doable.
that is my code:

add_action( 'init', 'myblog_rewrites_init' );
operate myblog_rewrites_init(){
    add_rewrite_rule(
        '([^/]+)/([0-9]+)/?$',
        'index.php?title=$matches[1]&chapter=$matches[2]',
        'prime' );
}

add_filter( 'query_vars', 'myblog_rewrite' );
operate myblog_rewrite( $query_vars ){
    $query_vars[] = 'chapter';
    return $query_vars;
}

Please assist me! Thanks each physique!