WordPress Admin CPT custom action to add_action securley

I write this PHP code in my functions.php but I was wondering if this the correct way to do it (best way and security)
Is this securely?
What about the use of wp_nonce_url in the link? (is $_GET request safer with wp_nonce?)

First, I create a custom link in edit.php of the CPT "reservaties" with admin-ajax to call add_action for doing some stuff

do some stuff after clicking on the custom link

Thanks for your advice!