So (if I understand you correctly) when you got your X in that you were waiting for (mentioned in a prior post), you did set it up as a new device and everything seems resolved?
The iPhone X on 11.1.1 is connecting when set up as a new device and I can make and receive calls adequately, and the SMS/iMessage functions are working correctly.
To be honest, however, the LG V30 still works better.
Setting up as a new device was not an awful experience. I still don't have everything on the X that I had on the others, but it's not so hard to fix.