Hello @Ernst Ranftl,
You currently cannot sort posts shown in the blog feed by dates in the Main Blog Feed and the Custom Feed, however, you can sort posts by dates in the Blog Feed made with Data: https://www.wix-blog-community.com/post/how-to-create-a-customizable-recent-posts-list
In the dataset settings, you can select "sort" and choose a published date:
Hope this helps!
Wix Blog Updates