Hi @AcidPi ,
Thank you so much for your answer, this is really helpful. I also noticed that the meta description and picture is coming from a product and the FAQ on our homepage.
I went and changed the meta description and made it shorter and included more keywords, and now the meta description we wanted is actually showing. Now its only the title left 
So you suggest we implement the code in our header.liquid? We use a bought theme from a third provider from Shopify Theme store.
Thank you again,
Johannes