They may make money off ads but I don't think they have any real incentive to lie about what they're doing. Because most of their users don't actually care. I would be curious if anyone knows of any scenario where Google has outright lied about what they do and don't do with information, because I've never heard of it.

For me, I moved off gmail for other reasons: my email is too important to randomly lose access to because e.g. their youtube AI thinks I'm spamming a channel on Youtube. I look at all my data in Google as if I might lose access to it forever some day, because someday I might, with zero recourse.