I went through the same issue and I have Galaxy S10. Even though Goolge released Android 11 I had to wait until my carrier do their own tweaks the OS. I have Verizon I was able to update not to long ago. If I was you check with your carrier. Because they are ultimately the ones who releases the approved versions to make compatible with their phones and network.
I'll do that then. Probably call the customer service line for AT&T. Looking online, all I see are dates when it was supposed to be released. On this app, it said that the update for my phone line is completed, which is why I'm wondering further what is going on. Thanks for your response.