I had it once with a failing SSD. Windows 10 ran fine, but when both X-Plane began locking up and getting the Steam DWE, I began troubleshooting the disk. I temporarily moved both my X-Plane and Steam library to an external USB 3 HDD and it ran fine. I replaced the SSD, moved the installs to the new SSD, and haven’t had any trouble since. Good luck. BTW, in my case the start/stopping the download had the exact same behavior as yours. Looks like the answer to the linked post was also hardware related, since replacing the data cable solved his problem.