Historically there are 3 main arguments for the existence of God.
The Ontological - a being than which nothing greater can be conceived.
Essentially if you think of the most perfect being than he must exist because existence is part of perfection.
The Cosmological - something can't come from nothing. But the physical decays so this something couldn't have been physical. Since Everything physical decays according to the 2nd law of thermodynamics(the universe is cooling like a stove)
The Teleological(considered the strongest) - If a watch has a watchmaker doesn't it make since the universe appears to be designed it has an architect.
These are the strongest arguments for the existence of God and our the ones theologians and philosophers have debated for generations.
Philosophers are good at that.
Ontological fails because it falsely asserts that a non-real concept can have any bearing on the real universe.
Cosmological, in addition to terribly misapplying thermodynamics, is self-contrary (it asserts nothing is eternal so there must be something eternal to make it). Ignoring that, it assumes any number of not-neccessairily-true things about existance and then relies on those assumptions to make its case.
The watchmaker analogy is just that: an unprovable (and often clearly misapplied) analogy that lacks any proof of validity.
FYI the sources and norms for theology are derived largely from John Wesley. They can be adjusted for more philosophical use by simply changing the scripture to an Outside Source. Wesley argued all beliefs are built on those 4 pillars working together.
And I think that's easy to disprove.
Tradition: then no new beliefs occur.
Scripture: Then no new beliefs are written down.
Think they've experienced: Now that I believe is one of the reasons for religious belief.
Want it to be true: should have been added.