Taxonomy terms not available for filter in Views

Problem/Motivation

Currently, displaying entities through views with taxonomy term filtering with depth is not possible, similar to the way regular content (nodes) is displayed. This functionality would be very useful in many situations. For example, if you have two entities, one with the term "Apples" and the other with the term "Fruits," where the term "Apples" is a child term of the term "Fruits."

Steps to reproduce

1. Create an entity type and subtype using ECK.
2. Add a "Fruits" term to the taxonomy.
3. Add an "Apples" term to the taxonomy with the parent term "Fruits."
4. Add a field linking to the taxonomy term in the entity subtype created with ECK.
5. Create a view to display the ECK entities.
6. Add a filter (or contextual filter) for the taxonomy term with depth - currently not available. You can try filtering based on the added field linking to the taxonomy term or add Relationships in the view based on the added field, but this doesn't fully solve the filtering by terms with depth issue.

For better understanding, try doing the same with regular content (nodes), where filtering by taxonomy terms with depth is possible.

A similar issue → was raised in the Drupal 7x version many years ago but was not resolved. I have created a new task for the current version of the module.

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes