i know it should have at least 16GB ram.
You can run everything just fine even with 8GB and RAM is not filled that easy, especially if you are using computer only for trading, but 16GB will be just fine.
More RAM is better but it's waste of money if you are not doing any intensive work all the time.
You will have to run wallets, apps and anything crypto related just fine.
but would love advice one Gpu, drive etc.
SSD drive is standard now, but go with Samsung brand with higher TBW.
You don't need any special GPU If you are not playing newest games, some heavy graphical work or using it for mining cryptocurrencies.
I would go with some Ryzen processor with integrated graphics, and you can always upgrade later if you want.