Theism is literally childish

[I_am_not_mafia]

Energy cannot be created nor destroyed.

If you're applying such laws, then you would also conclude that a universe existing as a singularity would continue to do so, unless acted on by an outside force.

Another unfounded assertion on your part here. It really is a nasty habit that you need to quit.

On what evidence do you believe that an eternally existing god is possible?

The existence of a universe with a beginning.

That is not evidence. It is just one possible explanation among others. As I said we don't know that the universe had a beginning.

Yet it still shows us that the process is likely similar even if the conditions were not exactly the same.

Cool, let's see the evidence.

The Urey-Millar experiments shows us that via the process of self organisation free energy can be used to build amino acids. We see the process of self organisation happen at every level, from the micro to the macro.

We don't try to define such mechanics because we just don't know. Similarly, you don't know how this vast universe could exist eternally in a singularity, what cuased inflation, or how life arose. Just because you speculate on such things doesn't make your speculations necessarily plausible.

You believe in the existence of something that you cannot define, have no idea how it could possibly work and which is indistinguishable from your own imagination and you are equating this with cosmic inflation and life which can be observed and studied. Why believe in something when there is no reason to believe in it?

Yet waiting for a statistically rare event has been shown to take time in practice on average. If I gave you a bucket load of 6 sided dice and you tipped them all on the ground, the probability of them coming up all 6's is a statistically rare event. If I gave you a task of doing just that, how long would you ask for to complete that task in the knowledge that you were likely to manage just that? This isn't magic, it's just a lower probability requires more time to happen on average. Now if we tasked every person on the planet to do the same thing, then we can calculate a much higher chance of success happening within the near future.

The difference is that we know the mechanics of how all 6s could come up, or how a particular lottery number comes up. We don't know the mechanics of abiogenesis.

Another argument from ignorance. We know most of the mechanics. We can even create artificial life in the lab.  We don't know yet know the specifics of what actually happened in practice.

We don't know that the universe had a beginning.

We're told it's 14 billion or so years old - that implies it had a beginning.

Evidence is that it was in a certain state 14 billion years ago and has been expanding ever since. That's not the same as being told that it had a beginning.

All we know is that at some point which we call the Big Bang, all energy and space-time was condensed into one small point. We don't know what happened before that. What we do know though is that since the Big Bang, energy cannot be created nor destroyed so is essentially eternal. All All matter in the universe has come from energy, so yes, the universe does seem to be eternal.

And again, if we're applying rules like the conservation of energy and matter, then we also should conclude that an eternally existing singularity would remain a singularity. We tried to get around this with an oscillating universe, but the rate of expansion of the universe didn't fit that model.

Another argument from ignorance and yet another unfounded assertion. There was no matter just after the Big Bang, I told you this before. The fact that energy cannot be destroyed does not mean to say that that the singularity should have persisted.