I try to create on iOS an application like https://f-droid.org/packages/app.fedilab.nitterizeme/ on android to help a friend have the same feature (so it actually does not need to be an app per se)
i.e the user explicitly authorizes it to responds to twitter/youtube etc. links and redirect them to non-tracking frontend or app (nitter.net etc. )
However my understanding is that Apple requires the app to put a special file on the domain to prove ownership.
Is there a way to workaround that if the user gives his explicit consent ?
No, there is no workaround for that