How to completely delete app from iPhone/iCloud including all saved data

Hello,

I'm currently experiencing problems with my Spotify app (Spotify Connect cannot find my devices). I've already tried to reset my iPhone to factory settings and if I install Spotify on the new, clean iPhone, everything works. But then when I restore backup of my iPhone from iCloud or iTunes, it gets back to the state where issue still occurs.

The only possible way is that Spotify has saved data somewhere and keeps restoring back to last state. Uninstalling the app and installing it via App Store again returns it to the state it was before (Spotify doesn't even ask for my login name and password).

I've been digging deeper and found out some Spotify data in SETTINGS -> GENERAL -> IPHONE STORAGE and also in ICLOUD -> ICLOUD BACKUP.

I've deleted all these Spotify data and turned off using iCloud for Spotify. Still when I try now to reinstall the app (BTW still there is a cloud icon in the App store when installing Spotify again) it always returns back to previous state.

So apparently this is not a Spotify related issue, but in general I just need to find out where those data are and delete them. Could you please help me with that please - any ideas what to check?

BTW also tried this: https://community.spotify.com/t5/Spotify-Answers/How-can-I-perform-a-clean-reinstall-of-the-app/ta-p/4746485

I'm planning to upgrade to iPhone 8 or newer shortly and am afraid that restoring the backup will leave me with non-working app again. However I'd also like to keep my iPhone 6 just to play music to my multiroom audio system as well.

Thank you!

• iPhone 6 Plus (MGAC2ZD/A)
• iOS 12.4.2

Regards

PJ