Breadcrumbs in Blocksy are implemented as a controllable layer from the Post/Page/Product Title module. You can read more in Page/Post Title documentation.
Show/Hide Breadcrumbs in the Title
To control the breadcrumbs’ display options (show/hide) in the title section of the post, page, product, etc,. navigate to Customizer > Single Post (or smth. else) > Post Title > Elements.
Here you can turn on/off the breadcrumbs element.
To change breadcrumbs’ font and font color navigate to the Design tab in the desired section. If breadcrumbs are disabled then design options are not accessible.
Integration With Custom Breadcrumbs Providers
Blocksy provides its own breadcrumbs functionality, but you may use the custom one which comes with SEO or Breadcrumbs plugins like RankMath, Yoast, SEOPress or Breadcrumb NavXT.
To do that you must have one of these plugins installed on your WP.
Navigate to Customizer > General > Breadcrumbs > Breadcrumbs Source and choose the source you need.
Picking the primary taxonomy: Integration with SEO plugins
Sometimes one of the posts may have two or more categories. And you may need to display one specific category out of all in the breadcrumbs for SEO purposes.
To do that, open the post in the Gutenberg editor and navigate to the Post tab. Under the Categories section there is the Select Primary section, where you can select the category you need.