iPhone keyboard opens and closes on its own, every 3 seconds approx.

My iPhone keyboard opens and closes on its own, every 3 seconds - whether I am actively typing or not. My iPhone 12 Pro uses only the native keyboard. This happens in every application, anytime I use the keyboard. WhatsApp, iMessage, safari, etc. It won’t allow me to share a video. But it appears and disappears as shown in the two images. I have done a soft reset, hard reset, reset keyboard settings, my iOS is up to date, closed all apps, etc. I’ve never had to post on a forum before but I am really stuck with this one.