Which block are you referring to? One of the ones from WordPress Core? something from CPTUI-Extended, our premium addon?
The wordpress core blocks. When I added a new post type called “blog”, there is now a “blog_categories” core block. Just like the categories list block. Except no data is being pulled in https://rareview.d.pr/i/UT7XAp
Based on what I’m seeing and am managing to reproduce on my own, I think that auto-generated block is meant to show terms from the current post, from that taxonomy. It’s feeling more Full Site Editing layout block than just an arbitrary block to show a list of custom taxonomy terms.
That said, I know that our premium CPTUI-Extended has similar abilities like what I’m perceiving you’re wanting.
https://docs.pluginize.com/article/cptui-extended-block/taxonomy-list-layout/
Choose the post type, choose the taxonomy, choose the terms to display.
That said, there may still be core blocks that do what you need, with a bit of configuring of their settings, just hasn’t been identified yet.