buying and selling rETH again for ETH is simply feasible once the staking liquidity pool has enough ETH in it to deal with your trade. This is Rocket Pool's pool of ETH that emanates from two sources: you are able to https://dev.to/cleopatramorris_d539d19ea/rocket-pool-the-future-of-decentralized-ethereum-stakingintroduction-1m2b