Most of cosmology is theories. Anyone who claims they know how the universe came to be is full of it. No one was there to witness it. Same with evolution

The big bang doesn't even refer to a big bang. Oversimplified name. It should be called the expansion of the universe theory, not the big bang theory.

Catholic priest came up with the big bang theory.

The data points to the big bang is the most likely beginning of time by a long shot. But not 100%. Hubbles law, background radiation, nucleosynthesis, and galactic formation all strongly support a big bang https://blossom.primal.net/f01d898a6e274bc432355039858818d4df91794d0cb6671e0c21f2cc8309a41d.j...