They're all based on nonsensical philosophical word games like the ontological argument or completely unfounded premises like in cosmological arguments and so forth. I see these grandiose claims from theists like "Natural theology has proven God exists", and "Philosophy made me a theist". Yeah I doubt that. I think you wanted to be a theist so you dove into obscure works of philosophy to convince yourself there's some substance to it. But all these philosophical figures, if you read their actual works, are effectively batshit insane and just write volumes of argle-bargle, and when you strip away all the obscurantism their arguments are incredibly weak or they give no arguments whatsoever.

Perfect example: Kierkegaard. People talk about Kierkegaard like he had some profound insights or argument for God that nobody else thought of. People say "I was an atheist, then I read Kierkegaard". That's absurd. He had nothing. His works are a big fat zero when you really analyze them. He basically says "Just have faith, and now here's twenty pages of incoherent nonsense about mermen and shit". Most of what he wrote is either completely indecipherable or self-contradictory.

Or you look at someone arguing for a specific religion like Islam, and it's even worse. I can't tell you how many times I've heard Muslims say "Just look at the beauty and poetry of the Quran, clearly this could not have been made by humans". Really? That's your argument? I've read the Quran and as I recall most of it is just Bible stories retold and the occasional threat of hell to nonbelievers. It's just another unremarkable, man-made religious text written by deluded people that probably wanted control over other people. If beautiful poetry is the criterion for divine inspiration, then Shakespeare is apparently God.

Or you look at arguments for Christianity. You often see for example diligently made arguments that the gospels were written earlier than previously thought, or more reliable than previously thought in some way. Is this supposed to be impressive? Believing in these miracles would still be absurd even if Jesus himself wrote a book detailing his life. I can watch videos of living eyewitnesses who say some modern-day prophet worked a miracle. I'm not going to believe it, and neither is the Christian. So why are you arguing that I should believe in miracles as attested to by disparate ancient texts that were written after the events by people that we don't know were eyewitnesses? If the bar is that low to believe in miracles, then you better be prepared to also believe that Muhammad split the moon, and that Joey Mormon found some magic plates in his backyard, and so on and so on (sniff).

I'm sorry this comes off so angry. I really am sorry to hold this view that theism is so vapid, because I want to respect the view of my theist friends and family. I was raised as an evangelical Christian but became very disillusioned and angry with it and theism in general. The anger comes from the fact that I see theists so often manipulating people and society in negative ways, and then I see them smugly justifying themselves with awful arguments. If you want a prime example of that, look up Anjem Choudary or Ken Ham or Ray Comfort. Actually, don't, because they should be ignored. But you're probably already familiar with them and take the point.