This is super helpful context on how the data enrichment process works. If you wanted today to get access to your data at the level of:

“user graduated in 2002 from X, is vegetarian but gets Uber Eats from McDonalds store Y and has never ordered a non-beef product in the past 10 months.”

Would you reach out to a company like acxiom to request it directly, or is identity usually completely abstracted away due to consumer privacy regulation?

Right, it depends on the advertiser network. I gathered some assumptions from the Social Dillema, https://www.youtube.com/watch?v=uaaC57tcci0 but the truth is a bit more nuanced
Do you think it possible to access or somehow purchase your data from advertising networks like facebook or google? If advertisers are able to get access, could you not buy it yourself

met a guy who started the company that creates those terms of service agreements that allow them to do what they want with your data