How Does a Hybrid PoW/PoS System Determine the Block Proposer?

In a hybrid PoW/PoS system, the PoW mechanism is typically used to determine the initial block proposer (the miner who finds the valid hash). However, the PoS component is then used by the validators to vote on and finalize that block.

For instance, in Ethereum's past hybrid model, a PoW miner proposed the block, but a committee of PoS validators used Casper FFG to provide a fast finality guarantee for that block.

What Is the Role of ‘Checkpointing’ in Achieving Finality in Some PoS Systems?
How Does the Concept of ‘Finality’ Differ in a BFT System versus a Proof-of-Work System?
How Is the Block Reward Typically Split between PoW Miners and PoS Validators?
What Is ‘Transaction Finality’ and How Does It Differ across Various Blockchain Architectures?
How Does the Finality Guarantee in PoS Compare to the Probabilistic Finality in PoW?
What Is the “Proposer-Builder Separation (PBS)” Model in PoS and How Does It Affect MEV?
How Do “Finality Gadgets” in PoS Systems Serve a Similar Function to Checkpoints?
How Does a Hybrid PoW/PoS System Compare to a Multi-Algorithm PoW System in Terms of Security?

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