DRK the least chunkiest or is it just me?

[Siete]

You cant help about it, the game is balanced around lvl 80 and there are some glaring issues in between 1-80 that are impossible to solve.
If it may help, in role actions you have additional 3 damage reduction tools.
Arms length that reduces mobs attacking you attack speed by 20%, Rampart which reduces incoming damage by 20% and Reprisal which reduces mobs damage damage by 10%, use them with Shadowall which you get at lvl 38 and it should be enough for lvling dungeons/etc.
Stunning big mobs with Low Blow role action also helps a lot.

Also i could asure you that GNB will never outheal DRK on the same lvl and gear.

I already make use of all those skills, even reprisal before big burst attacks.