Hey there bestusefultip. You and me too! I also have emoji wallpaper but not cinematic wallpapers. I'm afraid I don't know the answer to this one yet but I have been trying a few things that I thought might help and that other reports have said solved the issue. These are: leaving your device on charge over night and updating the Android System Intelligence app (apparently advice from Google support); updating Google Photos; clearing cache on the former two apps. Anecdotally some of these seem to have worked for others, but not for me. I think waiting until the next update might be the only course of action.
Update the Android System Intelligence app and Google Photos. Also, clear the app cache, but still facing the same issue. I hope the next update will fix the issue, and my Pixel 6a will receive the Cinematic wallpaper update. Thank you.