I hear you! And can totally see why it would be frustrating.
So we know for sure that your MC has resolved his personal problem and you think it was Good that he did so – his blind faith was a bad thing.
Can I ask then, why is he left so bitter and angsty? I’m not sure I understand this – he no longer has a personal problem (it’s been resolved), and yeah, there is a cost to having to let go of faith, but shouldn’t he be happier now?
In a joking way I want to ask, why are you being so mean to your MC? 
Especially because you said in the other thread that all the other characters are left feeling satisfied and not bitter.
But please bear in mind that this and my other questions are not because I think you are doing things wrong. It’s very possible your story is deeper than we (and maybe you) know, and that is making it hard to grasp. One possibility that springs to mind is the presence of a substory that has the opposite judgment.
Or I wonder, could you imagine one more denouement scene where he realizes that, as much as his new blind-faith-less worldview kind of sucks, there is some aspect of his life that is looking up now and it makes him smile?