ETH will be POS/POW during the transition period. It will eventually be a POS chain: https://ethereum.org/en/eth2/#:~:text=Eth2%20is%20a%20long%2Dplanned,to%20serve%20all%20of%20humanity.&text=Eth2%20will%20reduce%20energy%20consumption,more%20transactions%2C%20and%20increase%20security.