I am not an expert. I bought some silver American Eagles from APEX on line. They delivered it- no problem. I then took to safety deposit box.
Note: Check your homeowners policy- it may have limits on how much is covered if stored at home for things like gold, silver, jewelry, guns, and computers etc. which you may want to increase.
Do as you will, but I would NEVER EVER put cash or precious metals in a safe deposit box. Those are worthless except for documents. The gubmint controls the banks, so if the gubmint declares a "bank holiday" and closes the banks, you can't get to your PM's. Furthermore, the gubmint is quite capable of ordering the banks to seize any cash or PM's in safe deposit boxes, or at the minimum, open all of them and force the owners to explain to the IRS the source of said assets, and even tho you obtained them legitimately, do you want to be harassed by the IRS? There are any number of unpleasant scenarios that might ensue.
In short, anything you put in a safe deposit box is at the mercy of the Kenyan Marxist in the WH. You might be comfortable with that. I am not.