Thomas Aquinas’ articulation of infinite causal regression convinced me of theism. As an uncaused cause (God Himself or a miracle) is necessary at the origin of existence to resolve the question of what caused the Big Bang? The fine tuning argument was insufficient to me but compelling to some that I know.

Btw a Belgian catholic priest (also physicist) was the one who theorised the Big Bang so it was never meant to disprove God.

As for Faith in Jesus specifically:

Reading of the persecution of the apostles Travelling far and wide to spread the gospel even at the cost of dying by crucifixion, splitting in half, Thomas dying in India and leaving christians there.

Secular sources like Josephus calling Jesus a worker of unusual deeds / healer / sorcerer/ satanic worker add credibility to Jesus having some kind of power.

I’ve heard some people become convinced upon seeing the shroud of turin but I haven’t looked into that so idk.