Luckily there is a mobile phone OS and hardware that isn't produced by the world's largest advertising company, and furthermore doesn't allow two different corporations to be involved in the core OS of the device.
I hope you are not referring to the company that is pushing AI ads through their system settings, pushing Creator Studio subscription ads through the formerly non-shareware productivity tools, and pushing movie ads through their wallet?
Seriously, get a Pixel and install GrapheneOS, or maybe a Fairphone with LineageOS.
You'd still be walking around as a free advertiser for their stuff, simply by owning Google-branded hardware. And of course the hypocrisy of having a Google phone to avoid Google spying is palpable.
I doubt people notice that sort of thing. Maybe whether you have an iPhone or an Android at most. Avoiding Google spying isn't the point of GrapheneOS anyway
Apple isn't the largest advertising company, but it's a pretty big one. The only other candidates I know of are aftermarket Linux distros, but they have their own problems.