The bank reporting requirements are primarily to protect against money laundering. That is, obscuring the source or destination of illegally-obtained funds through instruments that don’t leave a veritable paper trail (eg cash). The mandatory reporting threshold in the USA is for cash transactions (whether deposits or withdrawals) is $10,000, but bank clerks are instructed to also look for other signs of suspicion even if the transaction is smaller than that amount (eg repeated withdrawals that conveniently are below the mandatory threshold).

But reporting just means the clerk might have to ask one or two clarifying questions, to fill in the mandatory report. They usually otherwise perform the transaction unless the bank itself suspects money laundering or fraud is happening right now, which is very rare.

I personally have bought and sold a few automobiles with cash over the last decade or so, and have had no issue handling low-five figure sums with banks and credit unions, apart from their clarifying questions.

In short, don’t bother with breaking up transactions into smaller sums or whatever. That will almost always garner more suspicion than just doing a single large transaction.

That said, are you planning to buy gold in cash? Do they not offer wire transfer or ACH payment options? Those have no reporting requirements, precisely because the paper trail is already created and is traceable with the right warrants.

(I have other misgivings about whether financial privacy has taken a back seat, the opposite of the robust communications privacy we currently enjoy. But that’s a different can of worms).