Playing Geneforge Mutagen here.

I'm not sure if I did something wrong with my build, playing a shaper on normal difficulty, and the enemies are taking a LOT of punishment to die (some take like... 8+ attacks sometimes) and my creatures take a LOT of damage (usually dying in 1~2 attacks)
i'm using 3 upgraded artilas and 1 ur-ghlaack.

https://imgur.com/a/HLg5B5A

Personally, I have had greater success with pumping up fire-shaping (for the fyoras, cyroas, roamers, and drayks). Some things are kind of resistant against magic damage, but less so against fire or physical (you can get physical damage when your creations are next to the foe, and then they bite the enemy instead of the breath weapon).

Watch the screen when your creations hit--you'll see something that mentions a number of points of damage absorbed, and if that number is high, the amount of damage that actually happens tends to be pretty low. It seems like that happens more with the magic types, though glaahks are still worth it for the stunning chance.