I purchased an unlocked Samsung S20 Plus 5G (August 2020) directly from Samsung. I have noticed lately that my phone is not picking up 5G signal on my AT&T service. Other people, including my wife with an iPhone 12 (also unlocked, AT&T) is picking it up in my area just fine. My phone just displays LTE+ where my wife's phone and others display 5G.
I have tried everything mentioned in the forums, and have called AT&T and have installed a new SIM card which didn't correct the problem.
I am suspecting there is some issue with the unlocked version of the S20+ 5G and AT&T 5G.
Please advise (as I mentioned, I have called Samsung and AT&T support and nothing they have suggested corrects the problem.)