Google has often used data acquired through their market position to start subsidiaries to unfairly compete with their ad customers.
The reason it’s unfair is because Google has not just the ad data but the web search data, this often results in a Google ad customer going from #1 google Organic search result for key terms, to #2 to Google’s competing subsidiary.
Worse from going from #1 to #2 to a google product, the natural instinct to save the business is to increase ad spend to be sure you are still the #1 ad to our place the google at the top of organic search, of course ad spend goes right into the pocket of your new competitors core business anyway, and in many instances googles subsidiary will start bidding for your same keywords so they literally can’t lose competing with your business rather the have basically acquired an off form of rent seeking equity or they kill your business and become the market incumbent.
Of course the kicker are those instances a google subsidiary gets a custom tool at the top of google results (such as Flights) above both organic and ads.