"Real work is basically work done around MS office applications (or its equivalents) mostly for professional purposes."
I use MS Office apps (mostly Word and Excel) for my business and I've been using them exclusively on the iPad Pro for the past 6 months mostly with no issues.
I will admit that on rare occasion there is something that requires an inconvenient workaround, but for 99% of my uses, it is fine.
As for opening files and saving them to the cloud, the MS Office apps are very much built around OneDrive. The same Office 365 subscription that allows me to use the MS Office apps also gives me 1 TB of space on OneDrive, so I do store my files there, and it all works very well together.
As for the issue of opening multiple files inside of an app such as Word, that is something that Microsoft would have to build into their app. Even on a PC, there is no such thing as opening multiple instances of the same app. There is one instance of Word open and multiple files can be opened inside of that one instance. Yes, they have built that capability into their PC and Mac apps, but have not built it into their iPad app. That is something that app makers have to do, not something for Apple to do.
If you think there are actually multiple instances of the same app open on your PC/Mac, then try force quitting one instance while leaving the others open and you will see that it cannot be done. Furthermore, try opening multiple instances of your web browser and login to the Macrumors forum on one instance but not on the other instance. You will see that once you login on one instance when you refresh the other instance it too will be logged in. That is because there is only one instance of your web browser open with multiple windows.
Do you have Skype on your Mac or PC? Try opening multiple instances of Skype and log into a different account on each. Again, cannot be done. There is no such thing as multiple instances of an app. It is multiple windows within the same app, and the same can be done on an iPad if the app maker makes it that way, as we can see with Safari in iOS10.