Current month variation in 3 letter

Hello,

Thank you for contacting Rank Math, and sorry for any inconvenience that might have been caused due to that.

Please place the following snippet to your themes > function.php

add_action( 'rank_math/vars/register_extra_replacements', function(){
	rank_math_register_var_replacement(
	   'monthName_half',
	   [
	   'name'        => esc_html__( 'Current month name (Half)', 'rank-math' ),
	   'description' => esc_html__( 'It will return month name (Half version)', 'rank-math' ),
	   'variable'    => 'monthName_half',
	   'example'     => monthName_half_callback(),
	   ],
	   'monthName_half_callback'
   );
});
function monthName_half_callback(){
	$content = Date('M');
	return $content;
}

You can search "Current month name" variable in the drop-down list, or you can use directly %monthName_half%.

Let us know if that works.
Please do not hesitate to let us know if you need our assistance with anything else. Thanks.