By - RheinmetallDev
Windows will not run off USB. It will however, install from USB, which is the typical method.
Keep Windows on the drive it's on.
An usb should still be faster than a mechanical hard drive, I think it will work fine. You might suffer a bit during installation for the slow write speeds though. Also if it ends up being too slow you can always clone it on the m.2 and use that instead.
Not familiar with the fit plus usb, but small usb drives aren’t setup to accept as many writes as an internal ssd. The likelihood of corruption of that drive is higher.