After successful neurosurgery, a monk questions his visions of a transcendent being or whether they’re symptoms of mental illness.

Solid idea. The main thing will be how the visions help him. If it was a detective whose vision were helping him solve cases, he has something at stake if he loses the ability. Obviously your monk isn't doing such a thing - or could he be? No he definitely shouldn't be a monk turned detective, but the visions need to be helping him some sort of way. Or harming him. Either way, there has to be something to lose if he denies himself these images.
Obviously he doesn't want to lose his phone connection to the big fella and his mates in the sky, but if his newfound powers are helping his friends and making him a better monk, then you have some stakes.

Does the monk perform the neurosurgery or is he being operated on? If so, why does this happen, and is that the cause of him questioning his faith? After that initial setup (in layman's terms, after a brain operation a monk has a crisis of faith) ... what happens then? What is the protagonist's goal, what are the stakes, and who is your antagonist?

Hey guys, thanks for the feedback.

"There's more to the story than meets the eye."