Gold purchase, via deposit

I noticed that there is a big difference in price sometimes on the same day on the price of gold, so I would like to trade physical gold.
to do so I would like to have your opinion if I can do that,
I have owned a certain amount of gold for a few years now al hamdoulillah, my gold trader near me (goldforex) has a new option and offers to buy and sell gold via a deposit chest, gold which will be purchased will be moved directly to a safe supervised by “BRINKS”. then payments are made to the bank account. and I would receive an invoice for the purchase of ownership of the gold and all the necessary documents of ownership and transaction, everything is perfectly secure
it is really an opportunity for all muslims al hamdoulillah, but i would like to have your opinion
is there a problem with this kind of transaction?
Jazak Allaho khayren

sorry , I modify my question because according to the gold seller, it is not financially interesting to buy and sell physical gold (in intra day), he advised me to trade commodities such as gold , silver, palladium etc, to direct me to the exchanges, can we do that?

not 100% but by reading this, it looks like you are just trading contracts (cfd trading).
And this is not permissible

salam, yes unfortunately I was too quickly in euphoria when I saw the price differences that can be between one point to another during the day, but unfortunately the “premium” and the commissions of the seller swallow everything the potential profit from buying and belly (even in the week), so this is just not interesting, what would be the solution to trading commodities in a halal way? (I mean other than physically buying)