Q. Is it correct to state that a Bitcoin miner has only two jobs:
- validating transactions
- creating a block to add into the blockchain
Actually, a bitcoin miner is only concerned with creating the next block on the blockchain, through a computationally-difficult problem. It is the role of bitcoin nodes to verify this proof-of-work as they receive these newly created blocks.
As reference, see https://en.bitcoin.it/wiki/Mining