GT Metrix and PageSpeed Decreasing

Hi,

My site was loading perfectly before I installed Klaviyo, I have another Klaviyo's alternative installed before and GTMetrix and PageSpeed were doing well around 99-1000% on GT and 90-93% on SpeedPage. I have Klaviyo installed as per recommendation. And I like Klaviyo for some other features that other alternative don't have but what I hate is the site speed decreases big time. Any recommendations that will help. I already read and followed this as per instructions but still the same. https://help.klaviyo.com/hc/en-us/articles/4425956184731

PageSpeed gone down to 60-70% from 90-93%

GTMetrix gone down to 82-90% from 99-100%

Hope there's a solution for this.