Contingency and necessity both involve lots of things you are turdpolishing of definition in pursuit of a 'natural' explanation.
Keep criticising the 'style' of the argument rather than the substance, that lets everyone know what a great point you'll pivot to soon... not right now, obviously, but soon...
What happens in space time is irrelevant to the explanation for the existence of space time.
But it is relevant to the attempted analogy that you dropped on its face.
The explanation that needs no explanation is necessary, by definition.
Except that your definition is implicitly assuming that space-time that you considered wasn't relevant a moment ago. Without time, the contention 'necessary or contingent' becomes a false dichotomy because without time you can't have either.
That which changes has an explanation for that change.
Yes, but that explanation can be internal - all the changes to the parts of the universe that we see are the result of other parts of the universe. Changes to a broader reality need not come from outside the reality.
Is contingent, you'll notice here that time is irrelevant here because it is change which is important.
How can time be irrelevant to change when, without time, you cannot have change?
So what is this timeless reality? Can it be demonstrated or is it notional?
It's notional, until and unless we manage to somehow gather some evidence.
what are it's notional properties
For the purposes of this, extra-universality and an infinite age.
How is it distinguishable from God?
It lacks overt homophobia and misogyny? Oh, and consciousness. And spite. And any allegations of a long-term plan. Amongst others.
What are it's properties?
No idea.
What is it's relationship with infinite time. What is it's relationship with time.
Possibly none.
With everything taking time and nothing being instantaneous, what about quantum entanglement?
Nothing within the universe, but we're hypothesising an extra-universal physics where our current understandings may or may not have merit.
And what about......quantum borrowing?
Is that HSBC's new mortgage plan? Is suspect, in the possible absence of time, they'd be reluctant to lend on a basis of compounding interest for obvious reasons.
O.