Disable secondary (5G) connection

I was hoping there were some more additions to this thread to keep it alive but, seeing none, I thought I would add my current situation. 

A couple of weeks ago I somehow started receiving Band n71 on my Nokia 5G router and my service went into the trash. Poor connectivity, dropped connections, huge latency, jitter and packet loss. Before it switched, I would get between 65 and 100 MB/sec download speeds, now I'm lucky to be getting in the 20's. Sometimes in upload tests, I get sub 1 MB/sec speeds and a lot of times the test will terminate because of lost connectivity.

Spent over an hour with T-Mobile Tech support (first tier) and she tried to force my connection to a tower that only had 4G. She was able to get it to connect for a little while and I was getting pre-5G speeds (+100MB/sec) but it somehow switched back to a tower that also has 5G and the router will prioritize the connection over to 5G, even though it sucks. 

Here is the different signal strengths between 4G and 5G:

4G: RSRP: -95dbm, RSRQ: -7db. (3bars)

5G: RSRP: -106dbm, RSRQ: -15db (2bars)

Hopefully I can get this issue escalated and somehow turnoff the 5G radio or premaritally connect my router to the site that only has 4G. Right now, since my iPhone is configured for WI-FI Calling, it is unusable while the the router is on 5G. 

My router is currently running firmware version 1.2101.00.1609. Anyone know when this version was pushed to the field?

Eric