As I understand, when miners add transactions to their candidate block from their mempool, they append the txn to the merkle tree, which requires more hashing, as well as the hashing/maths involved with validating transactions. Wouldn't all this waste some hash power for the PoW?
While writing, I am realising that obviously, there is an incentive to add more txns for fees, and also that blocks will probably fill up quickly, and all the computation required for the block and validation is insignificant in comparison to PoW. Is this true?
What portion of all the computational power (hashes) is for PoW, in comparison to other things?