Thank you so much for your support and every kind of help!
However, I came across another problem that broke the camel's back.
After getting the Left Shift to work as an NVDA modifier, I started to put more applications onto the machine. Dropbox is a thing I use on a daily basis, and when it turned out that the desktop app can't be installed on a machine with an ARM processor, and moreover, the Microsoft Store Dropbox App is more or less inaccessible, I just gave in. The computer is re-setting itself and I will return it.
Anyway, now I know a lot more about certain things, and I hope you do too.
So, as a screen reader user it is not worth it to buy a Miix 630. It's a shame, because otherwise it was a quite nice machine. The keyboard was quite OK to type on, although it was much thinner than on a normal laptop. I very much liked the fact that it had a SIM card slot and this was a big reason I ended up buying that particular machine. The log-in using face recognition also worked very nicely.
But this time the downsides were bigger.