How to remove menus section from WordPress theme customizer

Try nav_menus instead of menus with remove_panel()

function mytheme_customize_register( $wp_customize ) {
  //All our sections, settings, and controls will be added here

  $wp_customize->remove_section( 'title_tagline');
  $wp_customize->remove_section( 'colors');
  $wp_customize->remove_section( 'header_image');
  $wp_customize->remove_section( 'background_image');
  $wp_customize->remove_panel( 'nav_menus');
  $wp_customize->remove_section( 'static_front_page');
  $wp_customize->remove_section( 'custom_css');

}
add_action( 'customize_register', 'mytheme_customize_register',50 );

Hope this will helps you.

Thank you!