The old link I had bookmarked https://developer.genesys.cloud/devapps/#/analytics-query-builder
no longer goes there, and there is no longer a link to the legacy tools as referenced in the forum thread below, either. Was this just retired entirely? The discussion indicated that legacy tools wouldn't be retired until their refreshed replacements were live, but I'm seeing the opposite of that.
The functionality of the analytics query builder has been incorporated directly into API Explorer. When in edit mode (not in reading mode), the request builder tool will assist you in creating request bodies for any endpoint.
IIRC, the "legacy" query builder was a bit easier to use. This feels like a step backward in tooling to me. API explorer is great for most use cases, but the analytics query building in this is pretty painful.