ELI60 How would you know that Google doesn't have something "odd" in their Pixel phone?

I was referring to the Snowden leaks
https://www.theguardian.com/world/2013/jun/06/us-tech-giants-nsa-data

And how a lot of it can seem far-fetched and conspiratorial at first glance

Just to sketch a brief outline, Snowden worked as a government contractor for the NSA who went on to leak the NSA’s overreaching surveillance programs, one named PRISM which collected data from tech and communication companies. Although they didn’t create “backdoors” in the traditional sense, the program created a more streamlined system to funnel data back to the NSA, following whatever broad guidelines the NSA used to determine whose data should be obtained; with little to no oversight

I didn’t bring it up to raise paranoia, but to reecho the sound advice of exercising a healthy dose of caution and skepticism regarding big tech (or any tech) and the government, because honestly we can never know for sure, especially since the government has little inclination to respect our right to privacy and the Fourth Amendment

Also if you want to read a bit more about this
https://www.eff.org/nsa-spying/timeline
https://www.eff.org/pages/upstream-prism
https://www.theverge.com/2013/8/8/4602966/email-service-used-by-edward-snowden-abruptly-shuts-down-to-avoid

Google monetizes your data in two ways. First, by running it through its algorithms to sell ads to their actual clients (not you). They use and keep probably no much more than what is stated on its privacy policy and allowed by the user in the settings. They even have very ethical internal reporting system to identify and address privacy policy breaches.
Second, by selling your data to the government. That part needs to respect no policy, no settings, no GPDR, no CCPA, no law, no nothing. And you can bet your a$$ the government would pay extra extra (not only money, but favors) to be able to see what those high-threat-model people are using their GrapheneOS-running Pixels for. @minerva did the favor of linking some very relevant articles, and we also have the Twitter Files revelation that the government actually pay the companies for helping in spying and censoring.
So it’s not ad money that should go in the risk/reward calculation. Of course I’m not trying to imply that there are any such thing as hardware backdoors, just that the incentives might actually exist.