Single pixel line with canvas scaler,Single pixel line with canvas scaling

I am using CanvasScaler set to Scale With Screen size, reference resolution is set to Full HD (1920 x 1080), Screen match mode is set to expand.

How do i create a line, which will always be 1px wide no matter which resolution user uses? I would like to use the lines as a dividers, but i have not been sucessfull so far. When i created an image with width = 1px, then in some resolutions the “line” starts to flicker and it ends up with not showing at all.

Only solution i have found is Drawing a 1 pixel thick line in Unity - Game Development Stack Exchange, but it uses “constant pixel size” mode, which i cannot use to always keep all the information i need on the screen.