We have issue with Customising the order complete mail with tracking link

Hello ,
We face a issue where we are not able to customise order complete mail with shipment tracking link,
for shipment tracking we use plugin WooCommerce Shipment Tracking (https://woocommerce.com/products/shipment-tracking/)
after doing some researching we found the plugin has a meta key _wc_shipment_tracking_items which can be used to integrated Developers can use the helper function wc_st_add_tracking_number to add tracking info to the order. In this helper function, the field $custom_url is optional.
But after trying them we couldn’t achieve what was required and most importantly we also see more scenarios created in woocommerce emails but not see those scenarios in the email customiser .
To be more precise on this issue we checked and found this reposne from you people on wordpress forum where you have helped someone with custom shortcodes to solve this issue – https://wordpress.org/support/topic/integrate-custom-plugin-hook/
We also request you to help us with this custom shortcode which we can use it emails ..

2. Secondly we use this tool before different domain and then we moved it new domain as we shifted our shop , but we were able to create rules for language specifically , where English mails goes to English audience and Other languages accordingly but i dont see those rules in our current one though it is pro version ask you to help with this scenario as well