Sort sub field based on sub field value

Yes, you can. After getting group value, you can sort sub-groups using a custom function, like this:

$group = get_post_meta( get_the_ID(), 'football_league_table_option', true );
usort( $group, function ( $a, $b ) {
    $score_a = $a['football_team_win_stat'];
    $score_b = $b['football_team_win_stat'];
    if ( $score_a == $score_b ) {
        return 0;
    }
    return ( $score_a > $score_b ) ? - 1 : 1;
} );
$counter = 0;
// other code

Please check the field ID in the code. I didn't know which $prefix you used, so I use football_. Not sure if that's right.

Anyway, do not just copy and paste the code 😉