Thank you for detailed answer . I understand that a pool will not send the same work, and now I understand that even 2 solo miners with the same conditions will not get the same work .
My question is if it is the case what happens?
All blocks include a Coinbase transaction, which is where the miner creates new bitcoin and sends it to their own address (along with the fees gathered from all the transactions in the block) as their block reward. Even in the very unlikely case that two different miners include the exact same transactions from the mempool in the exact same order, their Coinbase transactions would be different since they would both be sending the block reward to their own address. Because of that Coinbase transaction being different, then their Merkle root will be different, and so too will their block header, meaning their two blocks will be be entirely different and require different amounts of work to successfully mine.
In the
incredibly unlikely scenario that two individual miners both chose all the same transaction in the same order, and generated the same Coinbase transaction sending the same coins to the same address, and used the same timestamp, and started at the same nonce, and so on, then they would simply duplicate the work needed to mine that block.