It is my phone. I do use a booster. It takes me from -122db up to about -71db (overall a strong signal). I have tried all the things that I could find. I was all the way to the point of jailbreaking my phone to be able to install low level software so I could control the band setting directly. Running a pretty big risk of bricking my phone. Until I finally read an article that showed that it would not work for me because I am on Verizon and they don't allow that access (period).
I understand what they are trying to do, they are trying to get everything to the higher 'better/faster' band, and phase out the older slower. I used to be able to stay connected to band 13 and use my hotspot as a secondary internet access. But months ago something changed and now it is always trying to get to band 2. And band 13 does not have bandwidth anymore.
So, I assume that in a year or so they will keep upgrading and things will stabilize and I will be able to get data on band 12, but for now I get very few bits. I will give them a call at some point and ask if there is anything that can be done. But prospects are low, and I could look at other carriers, but I am very remote, so I don't expect much from that exploration.
Or I can stick my phone up my ass...