If a PoW Miner Creates a Blank Block, What Prevents Them from Being the PoS Validator?

The PoA mechanism separates the roles of miner and validator. The selection of the PoS validator is randomized based on the amount of coin they have staked, not on their PoW contribution.

While a miner could also be a staker, their mining success does not guarantee their selection as a validator. This separation ensures that control over block creation and validation is decentralized across two different resource pools.