In the US there is a tradition of high ranking officials submitting a resignation letter to the president on their first day. If he is ever dissatisfied with them he doesn't have to fire them, he can just accept the letter they already wrote.
In Russia they do the same thing, but with suicide notes.
I sure would like to know why a bigger brouhaha hasn’t occurred over Presidente Zelensky whereabouts between tweets. Seems to me he is a president in exile in some very nice places.