Cardass has topaz and sapphire, which spawn at a very different altitude range as well. I’d suggest Malurialakrib for diamond.
You can look in the Creations → Worlds section of the forum to find lists of what’s on the home worlds, most of us are using external sites like boundlexx.app or boundlessinfo.com to view resources on various worlds.
The following post is very old but it has a great chart regarding resource depths that can save you a bunch of time. You were at a good depth for diamond, though.
I’d add more but this is just a morning drive-by of the forum 
There’s lots to do! I created alts early on for almost exactly what you list - except additionally a miner. It was good while I was exploring and let me do a lot but spread things a little thin once I settled in to some consistent habits.
Crafter is for sure - it requires all skill pages to be able to permanently craft all items.