I used CarbManager daily for about a year - opting for their “premium” app ($20-30/year?). I can’t speak to what data they gleaned from me and I do recall cancelling/deleting the account after I was finished. Great interface, smooth operation and data export features into spreadsheets, etc.
During that year of diligent data input I gained great insights into my macro-eating profile. I didn’t continue as I learned what I needed to learn about which foods contained what, and such detailed tracking does get somewhat tedious after a while.
Apart from the tracking policy about which I’m unclear, I can recommend CarbManager - btw, they also have a free version, which suggests, yes, we are the product.