Hi Paul,
That option mentioned in the threads you referenced is no longer available. It looks like it was removed as part of broader updates to how search integration works in Bing, possibly to align with Microsoft's evolving approach to web search.
Unfortunately, there’s currently no way to remove it. I looked into disabling it myself but haven’t found any method that works. The change was made on Bing’s end, so there isn’t anything available on the user side to modify or turn it off.
If you're open to trying a different search engine that doesn't include AI features, or at least gives you the option to turn them off, you might want to check out DuckDuckGo. In its settings, there's an “AI Features” tab where you can disable everything related to AI.
If you stick with Bing, I highly recommend submitting feedback by clicking the option on the lower right end of Bing's page.