Assuming you can't just directly filter it, and even if it's hard to run a high quality LLM locally for the time being, it should be feasible to run a smaller model on the returned output of large commercial models to identify and remove any advertising. Actually I wouldn't be surprised if you could plug a model for filtering malicious content from all web pages right into the local translation framework Firefox already has.

There is sure to be a great way to get google to express ads during a chemical weapon recipe though.

The second most enviable is locally hosting "Computer"

The entirety of the future Starfleet on our current timeline gets bricked whenever us-east-1 goes offline