Unsubscribe Link Token

All emails send through Arigato (Sendgrid, SMTP, etc...) it would be very very very useful (and only choice to be legal in our case in the EU) to include a shortcode (which might be very Arigato specific) to be able to unsubscribe. I am almost certain that other customers also already had that very same need. Shopify does have a liquid for that but won't work outside Shopify mails.

For example Mechanic took care of that like : https://learn.mechanic.dev/faq/how-do-i-add-an-unsubscribe-link-to-my-emails

Because now every email we send through Arigato (we are in the Netherlands) according to GDPR is illegal so we are now wondering if we should keep doing that. They do not include a one-click-unsubscribe link.