Some Microsoft apps not compatible

I use several MS apps on my Android 7.1 Tab A, but for some I get notified that my 'device is not compatible.' In particular I cannot install Cortana. Also, although I have been able to install the newly updated Launcher which does work, but does not appear to be entirely as described in articles. For example the menu, in the 'top right corner' of a browser, including Chrome, does not appear with its option to 'Continue on PC'. What is the explanation?

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