2d game but should i use 3d physics or 2d physics?

2d game but should i i use 3d physics or 2d physics?

I have found many 3d material is more readable and available. I have tons of tutorials on 3d and I know its some differences only but if you code 1 thing wrong it brings many issues/errors and wastes more time, so want to be sure beforehand.
not much on 2d out there also
I already have a lot of stuff done in 3d.
the reason I ask is

1 is using 3d vs 2d physics in a 2d game going to be more expensive (heavier load on a mobile)?

2 is there a performance issue vs the two?

3 it is a 2d game so it seems natural to use 2d physics, no?

4 what the major difference ?

5 please anyone who responds put your choice of what physics you would use in this line.

6 will game be slower with 3d or 2d physics?

thanks

Calculating 3D physics is significantly more expensive than 2D: I would highly recommend using 2D physics with 2D objects, especially if you are targeting lower-spec platforms such as mobile. It shouldn’t be difficult to create 2D Physics Materials based on your existing 3D ones.