Confirmation is not Validation
Miners are not Adjudicators
How does the 1-CPU-1 vote works
There is no voting system in Bitcoin. There is no counting of votes.
When Nakamoto wrote about voting in the Bitcoin whitepaper, they were using the word in an abstract, almost poetic way, not literally. Just as tigers vote for species of deer by choosing which to eat. Just as potholes vote for makes of car by choosing which to damage. In reality there are no ballot papers, no lists of candidates, no collection and counting of votes.
You could say that nodes vote by choosing which transactions and blocks to pass on and which to discard. That's a pretty weak association of ideas that might have some utility but which can also mislead. Don't make the mistake of thinking there is some more explicit voting system in Bitcoin.
successful solver of the hash wins the block
They don't exactly win the block, but yes generally one miner or pool produces a valid block before the others and their block is most likely to be accepted by all the other nodes in the Bitcoin network.
Someone could loosely describe this as winning the block but I think that sort of vague analogy is completely unhelpful and leads to the sort of confusion about Bitcoin that many people experience.
Some people describe mining as a race but it isn't a race where there is a fixed distance to cover - so that analogy can be misleading.
Some people describe it as like buying lottery tickets, where the more tickets you buy the more chance you have of winning. But it's more like a weekly scratch-card lottery where the revealed text almost always says "you lost" but the first person to find one of many that says "you won" gets the prize and all other unissued scratch-cards are rendered void.
Ultimately these analogies all break down and shouldn't be relied on. They are not the true explanation - they are a simplified story for people who can't or don't want to spend time understanding the subject properly.
So basically only the single cpu [...] is voting for the entire block
The successful block is created by one ASIC or other hashing device.
There is no voting or vote counting.
how is solving the hash saying that all the transactions are valid
All nodes validate transactions. They don't need miners to do that for them.
Miners are said to confirm transactions. That is because each successive block in the chain is described as a confirmation. Six consecutive blocks is described as six confirmations (not validations).
The confirmation isn't saying the transactions are valid, it is providing proof that the transaction history is increasingly difficult to forge. More confirmations means more certainty the payment is real.
What miners are really doing that is useful for the network is producing an ordering of transactions, a kind of timestamping of transactions. Once everyone agrees on the sequence of transactions, it is then easy to see which transactions are valid and which are invalid because they are attempting to spend money that has already been spent.