I think you're right. Seeing how he interacts with others, it's clear he thinks Balthazar will reward him. If he wanted to become Balthazar's vessel, then this would be his reward.
I kinda have a different suspicion which is that - looking at the big picture - taron may be even an ally as stupid as it sounds.
I think he is aware that its unequestionable that Balthazar is coming back and is afraid of it/him. He seems to work with/for the cult out of fear and is considered the vessel for balthazar (which he doesnt want to be lol as unlike most cultist, he isnt a believer).
I suspect hes kinda a spy in the cult and when he became aware of the timelimit of balthazars return, he started moving and killed the MC's parents as MC was lacking training and power from his perspective to ever get powerful enough in time.
Oren seemed aware of this too, as he saw Taron at the marketplace and knew it would begin.
Which did lead to the MC being trained 10 years by Oren, which gave him the possibility to become more powerful quicker.
We dont know how Taron made the MC come to the capital atm, he seemed unaware of Oren's death, maybe he just banked on the MCs thrist for revenge or knew Oren would point the MC towards him at some point.
After MC arrived at the Capital he kept throwing managable challanges at the mc like the orc beserker, sending him to get the chalice or the werewolf, fingding the mage in the same cell like eliza and getting the symbiote thanks to that seemed suspisciously easy too. He could have killed eliza at any point when MC was with the pirates if it was really just about torturing the MC for taron but he didnt do anything.
So i think in his own weird, merciless, gruesome way Taron is ... mentoring the MC.
It is very possible that without Tarons interferance, the MC would be a weak bitch when balthazar comes back in a few years and instakilled and the world doomed. Maybe Taron was the savior all along.
Even if that would be the case, he of course still has to die for what he did but i kinda feel like Taron already is aware of that he will be killed by mc and prefers it over becoming balthazars vessel which kinda would make me respect him.