How is it possible in a Kalium theme to change the title of the category or keyword view in a blog. Right now it is always displayed with e.g. "Category / *Categoryname*". How can I change the name and the separator "/"?

I already tried the plugin "Custom Archive Title", but that has no effect.

Thanks for the help!

[EDIT]

I want to costumize the the title when I do a filtering on the blog post site. E.g. when I filter the posts for one specific category, there is a title. And the title is now "Category / *Category name*" but maybe I want to change the seperator "/" or maybe I want to change the title completely. My client is thinking about to change it to a different name like "All posts by ..."

Is there a way to do this in a simple way?

You finde the site attached, and also an image.

https://bracciano.rafaelstarman.com/category/information/

Screenshot: