I probably should learn patience but like you all I like to update my firmware and software as soon as I know there’s an update. So rather than wait for the firmware to update on its own, I force it. This time I connected my AirPods via Bluetooth to one of my devices, in this case my MacBook Pro. I left the AirPods out of the case and plugged in to a USB-C wall charger, not the MacBook, but within range of the MacBook. I went to bed and by morning the update had taken.