Actually, I have never seen any kind of virtual keyboard on the Gemini. I wish there was a way to make it appear!
(Which is actually a bug in itself, as it deprives the user from things like multiple language layouts, emoji and the SFOS clipboard - but that is another issue.)
Whether I click or not on the alphanumeric icon, I can type letters and set an alphanumeric lock key
To unlock, I can type the alphanumeric lock key, even on the default unlock screen (without clicking on the alphanumeric icon)
If I click on the alphanumeric icon, I can still type my lock key, but nothing will show up on the screen (not even the **** indicating I’m typing something)