I should have known if the apps free, you’re the product. Duolingo appears to harvest the most data compared to other language learning apps.
Source: Surfshark Research
A bunch of these are also utter bullshit. “Purchase history” sounds like they can go through and read your Amazon purchases or something - they can’t. Diagnostic data sounds scary, but I’d rather use an app collecting diagnostic data because the alternative is a buggy mess. Them tracking what you do in their app is way more help than it is dangerous. Stuff like device ids and such are also likely only pulled for that reason or to confirm your purchases with them, etc.