This is honestly making Tanya's head spin a bit. "If you're sure they no longer work then I guess I won't try to understand how they did." This world contains so much that is frankly bullshit beyond her present understanding. Belmarniss is absolutely right that Tanya should be more humble. Some of the things she's telling her are probably false or exaggerated, but it's not as if Tanya can figure out which ones! Tanya really should rethink her position here and process everything she's been told in the past half hour.
So: there are beings (or one being masquerading as many) regularly empowering people with spells, and being worshipped as gods. Tanya thinks Belmarniss mentioned at some point that there are more clerics than wizards? That implies societal manipulation on a truly massive scale, but it leaves Tanya in the dark about what it might be for.
Well, does she have to concern herself with it? What does Tanya want out of life? Security, comfort, appreciation, making a contribution to society in an expected and encouraged way. Not living somewhere that offends her and paying taxes towards it, even if she personally is in a privileged position, but she won't risk her safety over that. What does any of that have to do with religions and gods?
Belmarniss said you can safely ignore gods (if not, presumably, their clerics) until you die. Belmarniss believes in nine afterlives, with people sorted according to how lawful and prosocial they were in life. Tanya... doesn't actually know that she's wrong? Being X said a lot of nonsense, which means she can't figure out the afterlives (if any) based on that, but if the gods here are telling people something, then - well, obviously they could be lying. Getting people to do you say in order to reach Heaven isn't exactly a novel idea. On the other hand, it's not as if Tanya is opposed to being lawful and prosocial, so she should hear out what they have to say. She'll visit Shelyn's church tomorrow, and maybe Abadar's again.
...getting back to what Tanya wants out of life, though, she still needs an income. Belmarniss suggested she might become (ugh) a bounty-hunter, that she be willing to kill at least specific people on the say-so of local officials if those people are credibly accused of capital crimes and present an ongoing danger to the public. The problem here is that Tanya really doesn't trust the local officials to convicting the right non-human in absentia! They seem more likely to be the kind of people who can't even tell nonhumans apart! If there's clearly just one person of an unusual species in a region, who arrived recently and definitely killed some people, that might be the the ideal case but it doesn't sound very likely to come up. Belmarniss said that churches sometimes coordinate things that are truly in everyone's interests, so that's another thing to ask them when she visits.