Can't open documents from onedrive in any of the office applications.
The issue is that the version packaged with Manjaro - stable (19.06.1-1) doesn't allow you to open up files from your onedrive. The only files you can open from your onedrive is if they are located in your last 8 "recent documents". Those will open in the online application when you click on them from the recent list.
Any other document whether you go to "Open from OneDrive" link in the Office application or if you navigate to the Onedrive and browse your files that way aren't opened in the OfficeOnline application. Basically it just does nothing.
I've tried both right clicking the file and selecting open in Excel (or Word if it is a Word document) as well as selecting the file with a checkmark and then clicking the icon at the top of the screen that says Open In Excel or Open in Word depending on the document.
I'm sure it shouldn't make any difference but the behavior is the same whether it is run from Manjaro-Gnome or Manjaro-KDE version.
As a side note, I'm not sure if this was based or branched from the ms-office-online (18.04.4-1) package that it replaced but that package works as it should in regards to opening onedrive documents in the various online applications.