1D and 2D are just mathematical abstractions. Everything is just 3D and that’s it. There is no time, just space with a state.
(I tried to explain better in comments so please check that. I would be glad if someone could give me a response to this brain fuck I’m having)
Yes, they are only abstractions, just like numbers are. I do not understand your conclusion that they therefore do not exist.
I still upvoted this, because I can see where you are coming from. It’s frustrating when adults portray thin flat objects as “2D objects” to explain dimensions to children. It’s not a simplification; it’s simply wrong.