I have had this issue since Jan ‘22 and have worked with both t-mobile and apple support numerous times yet the issue persists. For some reason, my 3rd party (non-apple) apps do not work on cellular data. i have tried everything tech support has suggested: reset phone, reset network settings, turn on roaming, ensure data usage is allowed for each app. it even went as far as me being advised by apple to redownload the current ios onto my phone and set up my phone from factory settings. this has been extremely frustrating and i would like to use my phone without such hinderances. can someone please help?