Multiple sites on woocpmmerce

My client has two domains/sites on woocommerce let’s say shop.com as the primary one for the canadian customers and us.shop.com for other international ones…

We have integrated Klaviyo and created a signup form but it’s only showing on canadian websites.. There are alot of other issues as well with managing multiple domains.. Like do we need to create a seperate account for both stores and if yes how because the klaviyo plugin is only one on woocommerce or both websites will have their seperate plugins on woocommerce?? How does this work and is there any easy way around it??  and why is this simple thing so complex