My carrier is Project Fi. I have found over time, and Pixel XL, Pixel 2 XL, and Pixel 3 XL, that my Project Fi phones will not receive an update until T-Mobile phones start receiving it. Once I see that T-Mobile users are receiving the update for the Pixel 3 XL, then I will hit "Check for update" and my phone will receive the update.
"Check for update" does work. However, there's nothing it can do until the update has been released for your particular carrier. Until that happens, the update isn't available for OTA download so tapping "Check for update" does nothing but tell you that your phone is up to date.
Unless an update includes something really special, and I want it right away, I don't bother sideloading, I just wait, and I usually don't have to wait very long. I don't think the November update includes anything "big," so I'll just wait for it.