There has been a reoccuring problem with the rogers app on my phone, I am unable to check the data usage on my phone becuase it says usage not available, this has been a problem on my oneplus 8 pro phone and has been like that for months. I have tried to disable, uninstall, reinstall, delete cache and data to even upgrading to a new phone and the same problem persist. It does work on another device which is really odd.
This sounds like a device specific issue since it works on another device. We do not sell or officially support the OnePlus so we cannot guarantee it will work with all of our services.
The only thing that you haven't tried that I can recommend is to factory reset your device and try restoring it fresh without your backup as a test.