When I got my AirPods Pro, there was an issue with a firmware update, that Apple recalled. Of course, it took me a while to understand it all, and I kept looking for updates (here and on Reddit). A new update was finally released, and I followed the steps in the article, and it worked for me. And the funny thing is, when the latest update was released, I didn't even realize it! It wasn't until I read about it here on the iMore forums. Immediately, I grabbed my 'Pros, and connected them to my iPhone, and checked. And I was happy to see that they had updated!
Why it's taking so long for yours to update is perplexing, but as
@Lee_Bo said: "Normal doesn't mean what it used to."