Do scientists know what happened before the big bang?

All possible theories governed by our current laws of physics cannot even simulate the first few minutes after the Big Bang (extra information: the four fundamental forces were combined into one "super-unified force" and we do not know how it works).

The generally accepted explanation is that a singularity used to exist before it collided with something (itself or something else) and the Big Bang happened.

We still don't fully understand what existed before the Big Bang; while the Big Bang theory explains the universe's explosive expansion from a hot, dense state, it doesn't explain what caused the initial conditions or what, if anything, existed before that event. Other theories that have been proposed include quantum fluctuations and multiverse scenarios; however, these theories are still speculative and the subject of ongoing cosmological research and debate.