The Snapdragon is enviable, but I don't think that ARM architecture is really up to scratch on Windows? Particularly in terms of software compatibility.
It depends... There are 2 levels of compatibility: 1.native support, 2.emulation. As the names suggest, native support is where the software is adapted/created with the ARM architecture in mind. This software is generally no different to the x64 version and runs efficiently. Emulation is where the application is normally made for the x64 architecture but still runs on ARM with an emulation layer. The problem is that in emulation, the tasks (even simple ones) are resource-hungry and therefore require a lot of energy and, depending on the task, can take a lot longer.
A lot of software already supports the ARM64 architecture, so I recommend that you check whether the software you are planning to use natively supports ARM64 or not. The advantage of this architecture is that it is very efficient, and when the software is running natively, this processor consumes very little power.
I myself have a Surface Pro with the Xplus, and apart from a few bugs (from Windows directly, not really with my apps/software), the experience is very good. The graphics card isn't very powerful but it can run some light games (but definitely not the main purpose, plus most games will run in emulation, which will drain your battery pretty quickly).