Yes, it is possible to walk while working. For me, between 2.5 and 3 km/h to type at the same time without too many typos. Beyond that, it becomes more difficult. But to read or consult a document, of course you can adapt the speed. Of course, it is necessary to have a desk that can be adjusted in height!

Yes, it is quite possible to put it under a desk to walk while working.
The minimum speed is 0.5km/h and maximum 6km/h in 0.5km/h increments