Hi Kate,
Thank you for contacting the Langshop team. I have tested the subdomain en.stilnest.com on the same gtmetrix tool and as you can see from the next screenshot https://prnt.sc/ruaz1u the load speed is much better than on your example. If the issue still exists for you, please provide the steps to reproduce it via ticket system or a live chat and our support team will be glad to help you.
Our Support Team is available 24/7.