They never do it. One rep even told me that my phone had to have that particular software number on my phone already before I could update. I've been having update issues with Att since my 8s plus. I thought it was just my bad luck. I've been having to ODIN ( already saw that you couldn't do that ) all the latest updates.
I wish I could do Odin on a Mac. Just realized it's not just a matter of not having Android 10, but I am still on the August security patch that came with the phone. This is just ridiculous. AT&T tells me it's a Samsung problem. Samsung tells me it's an AT&T problem. uBreakiFix is my next stop to see if I can get update flashed. I'm not optimistic.
Interestingly enough, I am remembering this same thing happened with my first Samsung, the S7, which was also purchased from Best Buy (AT&T branded also though). My s8 and N9 came from Target and Costco respectively, and I don't recall having the same issue. Probably just a coincidence, but I don't know. Google search shows this is not a new issue with AT&T Samsung phones, but not sure it's specific to where they were purchased.