I've beaten it a few times without cheese, I did not find the fight to be too difficult when avoiding certain larianisms. Shadowheart does enough healing and Gale and my main character warlock handle magic, and Astarion is a great damage source.
That being said, yeah, they are not a uh fair fight.
How exactly are you playing Astarion effectively without using jump/disengage, hide at will, backstab-spam, height-advantage-roll?
Eh, Arcane Trickster in the face of enemies when I feel like it. Despite low Int, many of the spells he can get are quite useful and enable some strategies.
He usually goes down at least once anytime I fight redcaps, not die, just unconscious so Shadowheart just raises him so he keeps fighting.
