This does not explain time starting at a point where time didn't exist.

It doesn't try to. Science is still trying to figure it out, which is the whole point.

It just defers the problem.

You say "defer", I say "still trying to figure it out".

If we came from a different universe then where did that universe come from? And the one before that? If we go on infinitely we can still never reach the present.

We don't know yet, but science is trying to figure it out.

If there was dark matter, or energy, or gas, wherever did that come from and what was before it? From nothing to something? If that dark matter existed infinitely before, how can we even reach the present?

We don't know yet, but science is trying to figure it out.

God being almighty and eternal is a solution that solves this dilemma of an eternal past, because God can create time.

A solution, but is it the solution? Until demonstrable evidence is presented, it's just a hypothesis like all the others. The difference is the other hypotheses give us something to test. Yours would have us just throw up our hands and say "idk, must be God I guess", which doesn't really fly in the world of science.

Edit: And you still haven't answered the question: Why do you need a scientific explanation for the beginning of the universe, the beginning of time, etc., but you don't need one for the existence of "an eternal and all powerful creator that is not bound by space or time"? Why hold up scientific rigour in one case, but accept with blind faith in another?