Mobile Broadband - Cellular Router - Poor Cellular Reception - Band Issues

Setup:

Mobile router: M6 Pro MR6500 

ISP: AT&T Mobility

Plan: Mobile Broadband Business

External Antenna: Waveform 2x2 Log Periodic MIMO

Area: Fairburn, GA

Issue: 

The cell signal at my current location is unusable. My M6 keeps locking onto a cell tower running B12. It has the highest signal strength among the other available bands (RSRP -109dBm, RSRQ -14dBm, RS-SINR -2dBm). However this band gives me no connection. No matter the time of day, the band gives no connection to anything. I have used methods to connect to other bands, that do work, however they are slow and unreliable. Without using band-locking all the router wants to do is stick on B12. I have purchased a 2x2 external antenna to help a bit with the issue. However it is nowhere near enough of a fix to say the connection is decent. I feel as if I have tried everything, and am losing it a bit. 

What I have tried:

- Band-locking

- External Antenna (Panel and Yagi)

- Refreshing Connection

- Calling support

- Removing battery and backplate on modem (for thermals)

- Changing APNs (broadband/nrbroadband)

- Scouting surroundings for possible high-interference. (Metal buildings, neighbors with cell-boosters, etc.)

- Hard reset device

From my research over the past few months. It seems to be a location issue. However, no matter which way I point my antenna it doesn't get any better. Ive done my best to use the FCC's website to map out cell towers, along with cell mapper, coverage maps, and google earth. I have it pointed at my cell tower (matching cell ID). 

I have been primarily using B14 (FirstNet) to do things for my business and write post like these. However, it is so slow, but the only one that works. I dropped it and just wanted to be content with the issue until the other day I got a 5G signal from Band 2 and Band 5. The issue with this is that when I band lock onto B14, I lose access to any 5G network capabilities due to DSS (Dynamic Spectrum Sharing). However if I'm not band locked all my router wants to do is be on B12. So it goes back and forth between the tower on B2/B5 (Great signal and speeds) to B12 (zero internet). 

I'm at a loss. Hopefully this post makes sense. I just hate the feeling that all my effort on getting my internet to work and research is all for nothing. (If I read one more reddit post saying to change DNS I will sob).

// I have info like, model.json (for the router) and Cell ID's if that helps just let me know.