I like and use Your keyboard primarily for the Android but also for the Apple. L
On the other hand I purchased on IBM Surface tablet and was very discouraged to find they support almost no usable on screen keyboards.
I can give you the list of features of your keyboard that they don't support, and of course some features that I'd like you to add.
But the major thing I would like to do is ask why you, as a subsidiary of Microsoft, can not convince them to allow you to have an alternate keyboard for their Windows 10 Surface tablets.
Note: I would be perfectly willing to pay for a 'Pro' version if that's what takes to get it your software moved over to their package