How to change the link for the language switch buttons?

Hi,

i have 2 languages. German (default) and english. I want the different languages only for blog posts. Not for the homepage or impress.

Currently on the homepage the german flag link to https://www.example.com/ and the en flag to https://www.example.com/en/home-english.

But i want to change it. The links from the homepage should link to

https://www.example.com/de/blog/
https://www.example.com/en/blog/

How can i do that?

Best regards
ebody