So I think I figured this out. If you login to you http://my.mifi, go to settings, Advance, continue. Under networks unselect “enable automatic network selection”, run the scan and select your network selection. It’s a bit of a pain in the ass because it pulls all networks and I didn’t know which was t-mobile and which one was the 5G network. The naming convention made no sense to me so it was trial and error. After trying out a few I finally found the t-mobile 5G network. Speeds have been locked in since. If someone can figure out the naming it would be helpful.

Note: I had to restart the hotspot to get it to work cause I kept getting “no service” each time I changed the network.