There are really any ads in Android itself, even with Google Apps installed. Which, by the way, you don't need to use even if they are installed (except, for example, Chrome to get a different app store or whatnot-, just like a fresh Windows install needing to use Edge to get Firefox or Chrome).

And it's still miles easier to get Android to switch default apps and also respect your choices, than to get Windows to allow you to switch default apps and then shut the fuck about their crap.