[General Questions and Answers] Billy_G_Oat:
I hope I can be of some help.

I recently ordered a Note 10+ 5G - Locked Verizon from a popular online re-seller. When I turned it on, I was greeted with an AT&T boot logo. I was pretty upset, but I though I'd try to get it up and running on Verizon before spending a couple weeks sending it back and getting a replacement. I tried Verizon's online software and I couldn't get beyond the IMEI change. It kept telling me that the Note's IMEI was what I was already using with my Droid, which was obviously not the case. So, I headed into my local Verizon store.

Nothing they did would get my 4G SIM to work, so they swapped out for a 5G SIM for free, then switched my hardware IMEI numbers and proceeded to have a some difficulty getting on the network. After doing a network reset, it seemingly worked. More on that below. I was getting both data and voice over network. I was able to transfer my setting, apps, etc from my Motorola Droid with Samsung Switch. The phone indicates both 3G and 4G signals as I travel around town. 5G is not available in my immediate area, though it is in some cities I occasionally travel to, but I'm unable to test that just yet. I become aware that there are differences between Verizon's 5G and other networks and it seems the non-Verizon phone I have is probably for the best in terms of compatibility.

Unfortunately, texts frequently take 10-30 seconds to send. Images, gifs and other non-text MMS can take multiple minutes to send and sometimes just fail. Other times the recipient will receive them twice. I feel like this may be due to the poor coverage at my residence. Further testing in areas of good to excellent coverage are necessary. I tried changing the network settings from Settings > Connections > Mobile Networks > Network Mode, but anything other than the default "GLOBAL" would result in a disconnect of data and voice services. The only way to fix it was Settings > General Management > Reset > Reset Network Settings. This would restore the Mode to GLOBAL and bring back data and voice services.

In an effort to remove the AT&T branding, I learned how to trigger a carrier switch, dialed the code and changed it from AT&T to XAA. That got rid of the AT&T boot animation and I was able to remove all but 2 stubborn AT&T apps. I noticed that my android version was 10 and UI was 2.5, so I set out to update.

This is where things got frustrating. Every attempt to update through the settings > software update was met with failure. Try again in 24 hours, it would say. I assumed this was because I was now using a Verizon sim on an AT&T firmware, but I wasn't sure. I thought I might be able to flash to a Verizon firmware, but after several versions and some more research, I learned that going from 976U to 976V was not possible.

So, over the course of several days, I learned a lot. I looked up the firmware releases on AT&T's website for the 976U and saw that they matched the T-Mobile and MetroPCS versions. So, I settled on a T-Mobile version of Android 11 / UI 3.1. It updated without any issues and even remained in XAA mode. No bloatware, no loading images, all settings and apps the same.

So, even though I have an unlocked AT&T Note 10+ 5G 256GB and you have a T-Mobile, the fact that we both have a 976U model, I think there is hope for you to get up and running on Verizon.

Hope this has helped.