if u want to work on your gear completely on your own u need it all.
If u just want to focus on gear, Weaponcrafting is the way to go.
Jewelry needs Armorcrafting.
Additionally, as a connection between them all, you need gems which can be crafted using alchemy.
Up to u. A short look into the tradebroker and the available designs (NPC) might give u a better hint if u want to make some profit.
they destroyed the whole crafting scene some patches ago and with the new patch you can farm almost every craftable item. But i think etchings are going to be surperior to the other ones (but this one could be very expensive lel)