If you are looking to sell out some into $USD to trade stocks or commodities with, I recommend Schwab.com . And if you want to do this and be invested in gold and still experience the degen level volatility that we get in crypto, I recommend checking out JNUG or GDXJ (3x Leveraged Gold Mining Stock ETFs). Of course this isn't trading the price of gold itself so make sure you take that into account. If you really wanted to you could always just buy gold. There are vendors who are willing to sell gold in exchange for Bitcoin or who make it easy to exchange between the two.
Also be careful of copying traders on one broker, it is very easy to follow a trader who is doing particularly well and then just never log in, but this is extremely risky. I do not trust other traders with my money so I choose not to use that feature. If you end up trading over .2 BTC on your trades there, you can play the role of the trader to be copied, and if people start following you you can make a lot of money via commissions.
i could go on about afrika forever lol, how we made them privatize their mines and then bought them, and now donate money to them to make ourself feel better, while we're taking their main source of income, but that's another story :-)