What is a nonce actually?

[Rdsigma]

So I'm in the first lesson and there's something that I don't get.
A hash is created out of a combination of the block number, the nonce and the data. Then the problem the miners must solve is to find the nonce that together with the data and block #, gives you the hash with four zeros upfront.

Here's what I dont understand: later it is explained that the nonce is the number of transactions you have made. So technically for a new adress the nonce would always start from zero and most accounts would have a nonce below 50 anyways. So wouldn't it be super easy to find then? Also all transactions of an account are public and easy to check. There's probably so much I'm missing here so if somebody can point me in the right direction it would be very apreciated.

Lastly with the latest eth upgrade, does the miner stuff still matter? Wonder how things have changed since that video was created and how these changes affected the EIP 1559.

[krakxn]

@Rdsigma

The nonce concerned with the txn is primarily for ECDSA verification (or public key recovery). It is just a arbitrary number which is used for multiplication to get some point on the elliptic curve. This is so that it is relatively nearly-impossible to guess that point, primarily serving as a security measure as well as for public key recovery.

Then there is the nonce concerned with mining: pending, reported txns from the users are stored in mempools (google mempools) by full-nodes (miners); the block, before starting to mine in PoW, contains these txns partly. This is primarily to "prepare" for the block to be mined, for it to have txns ready (essentially a prototype of the actual block). When the block is being mined, each subsequent block has an arbitrary number which is called the nonce which must also be "guessed" by the miners (serves as a security measure, as well as it being collision-resistant and therefore, no nonces are the same; it also follows that you can guess the nonce on a potato but--of course--the chances are negligible). Then, when the block is mined containing the txns, it has a block-header (which is the SHA256 hash of the data the block contains--some protocols hash the txns as well, and numerous variations). It is relatively much easier to verify as you just need to match the initial txns and the actual one by passing it into the hash function (SHA256).

EIP559 is primarily concerned with the gas-auction, no need to worry. A similar approach follows in PoS; it is just that the miner (validator) is "selected" randomly, with the initial approach being similar.