It is never good to hear that you are getting poor service on your iPhone XS Max, dlappen. What phone did you have before this? Any issues with it? What is the nearest intersection and zip code where you are having the issue?
The funny thing is, I too have the same issue with my xsMax after switching from a 8+. Before upgrading I consistently had 4 bars of LTE signal strength. I bring home my Max and immediately notice 1 to 2 bars at all times... It never changes!!
I have reset carrier settings, turned off and back on airplane mode, hard rebooted.... Everything that has been suggested on countless user forums... No change.
I do get a significant bump in signal strength when I'm not in my house, however with all previous phones I always had strong 4 bar coverage in my house.
Just wondering what the issue is with the network?
We understand the concern to have the best service, and device. Not all devices are made the same, and this could be related to the iPhone you have. We can help you troubleshoot to figure out what is going on in this location. Are multiple devices affected the same? Can we please have your ZIP Code? Are all services, calls, text messages, and data affected?