Disables tabs and media upload button in post content field. It also sets basic toolbar.

acf-form-disable-post-content-settings.php

/**
 * Disables tabs and media upload button in post content field
 *
 * @param $field
 *
 * @return mixed
 * 
 * @author Cadu de Castro Alves <cadudecastroalves@gmail.com>
 */
function rpa_hub_disable_post_content_settings( $field ) {

    if ( $field['key'] === '_post_content' ) {
        $field['toolbar'] = 'basic';
        $field['tabs'] = 0;
        $field['media_upload'] = 0;
    }

    return $field;
}
add_filter('acf/prepare_field', 'rpa_hub_disable_post_content_settings');