[Fitzcarraldo]

Outside of the current instance of our local universe (the matter, energy and events contained in the visible, expanding universe), is there any universal or absolute time standard?

[RadioAstronomer]

Outside of the current instance of our local universe (the matter, energy and events contained in the visible, expanding universe), is there any universal or absolute time standard?

Not that I know of. Time itself started with the Big bang. Thusly "before the big bang" is meaningless.

[RightWhale]

is there any universal or absolute time standard?

Railroad time is the standard time.