Hi Trauringe,
you can check your site performance with these online tools:
google Page Speed Insights
Pingdom
GMetrix
I don'T know the software Shopware, but if there is a possibility to use plugins or it is already in, you should use caching. The URLs seems to be from WordPress, is that true?
With caching plugin you can do all the performance hints from these pages as, lazy loading (only load if things are visible, minify JavaScript, css…, compress your images.
Cheers Fabian
P.S. If you don't answer, I will delete this link, because backlinking normally is not allowed here