[2D] Plane vs Plane collision without BoxCollider?

Hi, I am currently creating 2D side-scroller game with an almost infinite terrain.
You can see my previous question to see how the world is setup.

I’ve implemented a box collider for my initial collision solution, and my idea was something like this picture below.
using plane mesh and box colliders
So each map chunk consists of 1 large mesh and lots of box colliders. I mean lots.
Each chunk has 48x48 tiles, and each tile gets a box collider. yuck.
This solution doesn’t work because, it takes way too much overhead to initialize all the box colliders when player just wants to wonder the map from left to right.

10 by 10 chunks loaded
This is 10 chunks by 10 chunks map, which loads up in like a second.
Converting this mesh into mesh collider only adds a little overhead. With box colliders, it takes … forever.

How could I do 2D collisions in a case like this??
Please help me out.

Alright, I’ve solved it by NOT using planes and used mesh colliders.
Instead, I made each tile to be a 5 face cube.
(I don’t need the rear face for anything)

I’ll try to optimize it, so tiles like these …

00000
01110
00000

The middle tile doesn’t need LEFT/RIGHT face.
So I should not make those vertices.
This should reduce the vertices and should increase the processing speed.