While OSRS does have venom at vorkath, it's also not as hard on osrs. On osrs you can protect against the ranged attacks, there's more of a delay on the poison splatter phase, crumble undead is guaranteed to one hit the zombie spawn, and the fireball attack it does is also way more delayed and gives you time to dodge it.
Realistically you take way more damage at Vorkath on here than you do on OSRS and an easy way to mitigate that would be to remove venom from it.