I couldn't find alternatives to LinkedIn and I don't know how to filter out such content in a feed. The only thing that comes to my mind is to interact with content that you really like.

I know that Xing is pretty popular in Germany. [1]

[1] https://www.xing.com/

Why not unfollow all who present material that you find egregious or banal? Try and connect with people who are more interesting or more sympatico with respect to interests/fields/profession?