Making a brick texture darker

Your image is not the right representation of the sample you have.

On your reference image, the mortar is lighter than the brick, but in your image it is the inverse.

On section B you have more or less the same mortar color but darker bricks so you notice more the difference.

This probably can be solved using a different texture. Masking the mortar will not work because it is clearly a shadowed zone.

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But if the ratio mortar-brick is not that important, let's understand now how darkening works using curves.

The trick would be darkening the image while maintaining the light areas (mortar) more or less the same lightness.

Doing this with curves will increase the contrast, but also will saturate the color more and that is probably what is not working on your tests, probably making your images reddish.

So besides using curves (B, I lowered a central point on the middle) you need to desaturate the result (C).

In the photograph, the bricks aren't really a different colour. It's just that they're in the shadows, and so that part of the image is slightly less exposed.

So, with that in mind, perhaps try this method:

1. Convert the image layer to a Smart Object (Right click on the layer name, and choose Convert to Smart Object)
2. Do Filter > Camera RAW Filter
3. Adjust the Exposure and Colour Temperature sliders until you get a match.

If you need one version of the bricks to have some darker bricks, then I think you might want to consider using the Burn tool to darken some manually.