404 errorThis should help you get to being able to read the phone.... don't do the parts on here where they start writing stuff and modifying settings on the phone of course.
https://forum.xda-developers.com/nex...g-lte-t3042373
Once you get QPST reading the phone send me back a message... I'll tell you what settings I fixed.
I also got an xt1806 recently, unlocked on Verizon. I'm in a pretty rural area and speeds are pretty spotty due to obstacles between me and the tower.
Though it does stay in LTE most of the time, on band 13. I'm using LTE Discovery app off of the app store.