The problem with Klaviyo's Javascript is, that it loads all images of the forms, triggered or not, on all Shopify pages. Thus, impacting your Core Web Vitals Pagespeed score to the negative. We've seen stores that decreased by 20 or more points after installing Klavioy's app.
Load the Javascript of Klaviyo only on the pages where you actually require it, and block it from the rest. Unfortunately Shopify doesn't have such a functionality by default. That's why we created an app to reduce unused Javascript on your Shopify store.