The ads you're going to need to worry about are not going to be shown on webpages.
https://sandstormdigital.com/2025/10/16/openai-is-building-i...
https://www.contentgrip.com/openai-internal-ad-infrastructur...
Another local LLM extension that reads the output and determines if part of it is too "ad-ey" so it can hide that part?