What problem does this address?

When designing a taxonomy/term archive in the site editor, it is often necessary to separate out post types. This can now be down by adding multiple Query Loop blocks and setting the post type for each. But when it comes to restricting them to the current term, there is no way to do that dynamically.

What is your proposed solution?

When editing the Query Loop block, and then clicking in sidebar Filters > + > Taxonomies, each field should have the option for "Current term". This option should show on input focus (ultimately I think all terms should be shown as checkboxes, just like when adding Categories for a Post). Maybe this option only shows when editing a Taxonomy archive.