> I bought a purpose-specific, old model iphone from "Back Market" with no SIM card, very briefly allowed it wifi access long enough to download the "Lingo" app, then set the phone to airplane mode. Dedicated, throwaway email and AppleID.

None of this actually matters if you went through the steps to use the app. The app is designed such that you agree to the terms before you can use it.

You can use all the throwaway emails, devices, VPNs, and other tricks in the world, but unless you can reliably demonstrate to a court that you were utilizing the app in a way that didn’t involve accepting any terms of service then they could simply demonstrate that it’s part of their app flow.

Even using tricks to utilize the device outside of the app wouldn’t help, because they could simply demonstrate that you weren’t using it as designed or intended.