Perhaps you just have a different view on what is or is not an ad. For example when I see a link in the start menu for an app that I did not install, I consider that to be an ad. The most common time this happens is for Office. (Or Microsoft 365 or whatever it is called now.) Also, when I see a ‘suggestion’ to sign into a Microsoft account to use OneDrive - I consider that an ad. Microsoft aren’t telling me about OneDrive to improve my life. They are telling me to improve their profits. And when I type something in the start menu to launch an app, any result that comes up that is not something I put on my computer is an ad. It often will suggest particular websites for example.
These are the kinds of thing that we’re talking about. I’m sure if you’re using Windows on a home computer you will have seen these things. (I assume you’re talking about ads in Windows. It would be quite something else if you’d never seen any ad anywhere.)