buying gold is legal in us/europe but it is much regulated than crypto
How it is regulated, what are this laws, how difficult is to accept them for a common citizen?
Super easy and at the click of a button. Now, you have several alternatives: physical gold or a gold EFT of fund. The first one is obviously physical and you can store it, bury it, hide it in your cavities if you have to run, ... although diamonds tend to be better for that.
The problem is that you will be charged a large fee on top. Usually, it is also registered and the estate knows you got it.
If you are simply investing for speculation or storing value, perhaps an ETF is your thing. It is quick and simple with any trading account.
Now, you must be aware that it is ofte illegal to cross a border with your gold.