I have a Samsung Galaxy S5. I have never had a problem before staying in 4G LTE mode. For several days now however, it has only topped out in 3G and even drops to 1x frequently.
I have updated everything, and tried both soft and hard resets.
I have tried a device health check and it shows no problems in connectivity,
I have tried the settings explained here (it was defaulted to the top one):
https://www.verizonwireless.com/support/knowledge-base-97665/
The first two settings will connect to 3G, the bottom won't connect to anything.
I'm out of suggestions I've found online. Any idea what to try next?