What is quantum?
Don't worry about it. It isn't important. If you have made it this far in life without quantum, then just skip it and the migraine.
Quantum is a collection of rules made up by people who are, let's be honest, guessing why thing are happening that they can't explain in any other way. Scientists always want things to boil down and become more simple. They want finite lines and roles. When you divide and define, things are supposed to start making sense dammit. Some very smart people refuse to admin that maybe things get more complex as you get smaller, as you dissect. There are more choices instead of less for things or more interactions not less. Maybe those things you think are small are still just as complex and varied as all the big things.
The stuff the universe is made of. The material that can become anything on the smallest scale possible. These are buckets full of generic particles and forces that make up everything else.
The free memory in the simulation we all live in. These particles are the bits of random access memory that still have some traces of what piece of the universe was remembered at some point. Black holes are probably just memory leaks in the galaxy or sun subroutines.
No two things can occupy the same spot at the same time. Quantum is simply the act of very small things trying to keep out of each other's way. This is why they appear to travel faster than the speed of light. This is why they appear to change attributes or design without explanation.
The drone of creation. The soup of matter and happenings and changes.
Proof that God will always throw more at us. We are not in danger of figuring everything out and thus stagnating.