How I look at things:
Draw a line on a piece of paper.
2D right?
No.
Nothing’s 2D.
Nothing’s 3D.
Our cognitive systems pretend such things really exist. Our mathematical systems – EXTREMELY USEFUL as they are act “as if” such things are real… but – they’re not.
Useful yes. Practical yes. Real? Only in skeletal form.
There’s always an ‘up’ direction from the paper; it’s always bumpy. It has a start time before it existed and an end time where it no longer exists, and an observer that causes it to actually matter.