Tax_Query using WP_Query not working

You aren’t looping through the results. Here is your code:

$m = new WP_Query( $myquery );

if ( $m->have_posts() ) : $m->the_post();?>
       <ul><li <?php post_class();?>><a href="https://wordpress.stackexchange.com/questions/83409/<?php the_permalink(); ?>"><?php the_title(); ?></a></li></ul>
<?php endif; 
wp_reset_postdata(); ?>

There is no Loop. You just check for the existence of posts, echo some information about the first one and quit. if is not a Loop. It is a conditional. You need while.

You need:

$m = new WP_Query( $myquery );

while ( $m->have_posts() ) : $m->the_post(); ?>
       <ul><li <?php post_class();?>><a href="https://wordpress.stackexchange.com/questions/83409/<?php the_permalink(); ?>"><?php the_title(); ?></a></li></ul>
<?php endwhile; 
wp_reset_postdata(); ?>