Two post-process materials conflicting and can't use actual scene colors

I would like to create a post process into my Unreal to make a pixel art look like this from Yoan Petkov

I started by creating a cell shading post-process and, after trying many, finally followed the one from Prismaticadev. It looks kind of Ok.

To make the scene colors look like actual assets and lights colors, he is multiplying the desaturated shades by a normalized SceneTexture PostProcessInput0 wich makes sense.

The problem is that, to make the material working, it has to be set AFTER Tonemapping.
BUT my pixel shader (wich consists int this simple technique[One EASY Effect to turn Your 3D Games into PIXELART - YouTube] ) is after Tonemapping too and, when the two are active, it creates artifacts ( a bit difficult to see it on a screenshot but it’s strongly self-evident animated)

When the cell shader is set BEFORE Tonemapping, it just don’t works because of the previous nodes I shown you (don’t know why but I know it’s caused bt them)

And when I disconnect the problematic nodes, it just don’t show the colors and everything is just white wich is a big problem.

What I would like to solve is:

-either making the cell-shader work before tonemapping with the techniques of Prismaticadev.

-either finding another way to show the actual lights and colors of the scene

-or finding another way for pixelated look to work without conflicts (and maybe create only one postprocess material but I don’t know how)

(btw, does anybody know how to make the shadows clear and not having lots of “undecided” pixel that switch between shadow and light 20 times a second?)

If you know anything that could help all of this, it’d be really really appreciated :slight_smile: