Tell us what you are trying to do?
I want to display the category/taxonomies as grid.
If i build it with blocks i only can display posts but not categories.
Is there any documentation that you are following?
nope.
Only Post views can be created using the view block. To create a taxonomy view you will need to use the classic view setup.
If the classic view hasn't been enabled you can enable it by going to Toolset -> Settings and scrolling to Editing Experience. From there I recommend that you select " Show both the legacy and Blocks interface and let me choose which to use for each item I build".
This will allow you to have access to the classic editor as well as the block editor. From there refresh the page and go to Toolset -> Views.
You should now be able to create your taxonomy view. Then you can insert your taxonomy view by using the shortcode [wpv-view name='my-view'] where my-view is the slug of your view.
This is something that is in the pipeline however I cannot give an estimate as to when this would be implemented.
However the alternative of using the classic view editor still remains. It should be noted that the content template for the view can be built out using the gutenburg editor.