https://codex.wordpress.org/Function_Reference/wp_editor
The second argument for the wp_editor() function is editor ID
In the above for loop – all of the editors had the same ID
Changing
<?php wp_editor( wp_kses_post( $benz_tab_content ), 'benz_tab_content', $settings ); ?>
to
<?php wp_editor( wp_kses_post( $benz_tab_content ), "benz_tab_content_$y", $settings ); ?>
allowed me to give each editor a unique ID — per the counting variable.
The editors ( as many as needed ) are loading fine now.
Going to leave this up to help anyone else looking to dynamically create wp_editor()
fields based on a counting loop