This is a terrible study with no metrics on data amounts compared, and is most likely a pro-Apple agenda garbage article. The most authentic analysis on this subject is done by Douglas Leith here: https://teddit.net/r/privatelife/comments/mh9gt3/pdf_mobile_handset_privacy_measuring_the_data_ios/

This is bullshit, and how do anyone knows? is closed source… nobody can know, you have to trust their word… so… we all know how that works. lol