If there is no reason, existence is an awful lot of work for nothing. But if there is a reason, there must be something having the reason. So why is there that something instead of nothing? And why is that something's reason there instead of nothing, and that something's reason and that something's reason... Sometimes one needs to 42 such things and come back to them later.

I simply cannot imagine 'nothing,' but it's a damn good question.
Some would say 'god' IS creation.
As an 'agnostic neo-deist,' all I can say is, 'We might find out some day, but for now, it's a mystery."
But since you asked, we all know energy/mass cannot be created nor destroyed, so as far as we know, the universe has ALWAYS been here, always changing shape, expanding, contracting, like a lung, beating like a heart.
And will always be here.
Similarly, WE will always be here, in one form or another, for eternity.
Just a thought.

. . . a very good read :

[goodreads.com]

I would say "space" the thing of volume AND distance that is "nothing " other than what could be give relative measurement or considered infinite in every direction.

Space, I would not consider as being something that could be created or destroyed. I would consider that EVEN if there were not points in space to give for any measurements, the space of infinity in every direction would still exist, has always existed an DC will always exist.

Space is not a thing, it is nothing that th iij NHS are in and can be given quantitative measures between points at different locations in space.

Space, the thing that is not a thing, yet it exist. The existence of non-existance.

I don’t know.