just find a dvergr place with a fire mage inside. lure an enemy to the location or simply wait inside during the night till something comes around. the mage will level half the tower and most likely the component create aswell. once its broken they dont care if you pick it up and wont become hostile.
i never attacked them so far and this is how i got my first dvergr component by accident when running away from a 1 star soldier into a dvergr tower^^. which you only need 1 off to make the sap collector. multiple dont hurt but sap really isnt hard to come by with even just 1-2 sap collectors as its generated passively even while youre not around.

the bottleneck material early on will be soft tissue. most of this is found inside these giant stone skulls. some are inside dvergr digging sites but these seem rather rare compared to thier towers. but alot of these skulls are also found in the wild unguarded by dvergr. 1 skull is like 60 soft tissue. which is 60 refinded eitr. and you dont much eitr for most of the stuff aside the magic staffs and armor if youre into magic.