Consider deprecating old models API

**Feature request**
It would be great to have compression for helpers.

**Use case**
Many users need this functionality for production deployments.

**Implementation idea**
Add a new config option `enable_compression` with default `false`.

The title and body describe different work: deprecating an old models API versus adding compression for helpers. First inspect the helper and configuration entry points to determine which request is intended and where enable_compression belongs. Done should mean the agreed behavior is implemented with a default of false and verified by the relevant existing checks.

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