The Tavern

The boulder beetles does so much damage and is very difficult to escape, are they too hardcore? Perhaps they could do less damage?

They do a lot of damage per hit, yes, but they don't hit very often, and that makes them fairy easy to escape from if you're not ready to kill them yet, although depending on the situation, expending a consumable may be required. In particular, their tendency to blink away makes them very easy to escape using stairs or a scroll of teleportation. Unless a character hasn't invested any skill points in defenses at all, they can generally survive a few hits while escaping, in my experience, and once some moderate skill in dodging and/or shields is attained, their attacks aren't so threatening. Then again, I don't usually play super fragile species like Felids, so my perspective may be a bit biased.

Been playing as a Deep Elf Ice Elementalist so i guess i'm quite fragile until i get my hands on some higher levels ice spells, like Ice Cloud or Ozocubu's Refrigeration. Blink spells, or haste etc. are helpful to get away from these critters.

They have 40 Willpower, so hexing them should also be possible if you have some means for that available.

I play mostly octopodes. The EV-ignore 64 damage hits are a bit much, honestly. Same with the frostbound invokers(?), the new monster type in vaults: EV-ignore/shield-ignore frozen ramparts in very tight vault layouts need rc++(+) to not die in 2-3 turns.

Unfortunately I don't have any good solutions to that general problem.

EDIT: the roll-attack is dodgeable, I missed that - but seems at severe penalties somehow?