Checkout cross sell takes too much time to show products

Hello,
I have set the plugin to show related products in the checkout page, however the section is empty and gets populated with suggested product only after few minutes. Is there a way to make it faster?

example, add this product to the cart and proceed to checkout:
https://new.sptm.it/product/ottodame-maglia-39/

In the second step, the products will not appear right away, but only after many seconds. I duplicated the wesite in a local environment and removed many products and they are shown almost instantly in the chekout.

Thank you