It's odd, but try to go adventurer talent asap.
It doesn't boast any stats, but when you get rest or trans mastery up a bit, you can do advanced shadow missions with higher leveled friends right off the bat. It's easy exp, easy money for better equipment, and you won't have to waste time with basic shadow missions which is basically 1-shot mobs for 600g and 5k exp for finishing.
Hey man, i did defeat the shadow warrior basic until level 100, then int until their method was released.
And that's all i did until overpowered golems ruled the land.