I noticed this was missing as well. There's a setting to turn mobile data off and on but it doesn't look like the typical screen on Android, right? I just started researching this bc I had wished it was there as well and today I downloaded the Canon print app...For some reason it wanted me to toggle off cellular data and when I clicked the shortcut in the notification to go to settings it took me directly to the screen I didn't think existed where it shows the standard on/off toggle and a graph showing data usage with the option to set data limits. Can not find a direct way to get to it, but I know it exists now, which makes it even worse.
---------- Post added at 04:53 PM ---------- Previous post was at 04:02 PM ----------
After a little more thought I think we can take advantage of this hack. Settings/data traffic management/traffic reminder settings allows you to set limits on data usage, but mine was always wrong because the start/end dates for my plan couldn't be set. It's a one-time hassle but downloading the Canon print app to get to the standard Android data usage screen allowed me to set the start date for my plan and after that we should be able to use the more advanced options of EMUIs traffic management. To be more specific about my process...Download the Canon print app, launch it. It will begin the setup process. All you have to do is accept terms for the first 2 screens and after that there's a notification to turn off cellular data, click yes to display the cellular data settings screen and you will get the standard Android data management screen that we all know and love. Setup whatever you wish. For me just being able to set the plan dates was all I needed, however you can always get back to this screen through the same process if you want to use it for other settings. Just don't actually turn off cellular data or complete the setup for the print app and it should run again any time you launch the app. If it doesn't, go to phone settings/apps and clear the memory of the Canon app to start fresh. IF you're like me and already have a Canon printer and use this app, you will have to setup you're printer again if you clear memory but you'll just need to do this once to set the plan dates then use EMUIs traffic management so that you can actually use the Canon app for your printer, but if you don't have a Canon printer you can use the app to get to this screen whenever you wish. I hope this helps someone. I know I'm thrilled just to be able to set the plan dates bc without that option all the traffic management stuff on the phone is always wrong and completely useless. Good luck!