Hello @WriteWithTalkToWalle,
Welcome to the Klaviyo Community!
Although we don’t have the exact connection for WooCommerce coupons like we do with Shopify and Magento, you can certainly still send unique coupon codes. In order to do so, you’ll need to supply the unique coupon codes to both Klaviyo and WooCommerce via a .CSV upload. This would then allow the coupon codes to be recognized in WooCommerce when checking out and for Klaviyo to randomly distribute them to your recipients in emails. I think taking a look at both the How to set up coupons for WooCommerce and Use uploaded coupons in a message subsection of the Getting started with coupon codes in Klaviyo Help Center articles will give you a better understanding of how to set this up.
Additionally, I know that @TRIBE has recently released a new Klaviyo Toolkit plugin which helps alleviate this sort of limitation between WooCommerce and Klaviyo. You can find their setup instructions and guide on this plugin from their How to dynamically generate single-use coupon codes for Klaviyo with WooCommerce article.
I hope this helps!
David