Question about material (tiles) showing different colour or shade when it is repeated

When trying to apply a tile-like image, it appears very “blocky” as there is a huge colour difference on a surface larger than the material’s size. How do I solve this issue?

Learn about seamless texture. And texture dimensions.

That literally looks like it left side of the texture is darker than the right side - I think you need a different texture

The original surface was not evenly lit and as Adam indcates that makes the texture darker on one side than the other. You could edit the image in an image editor and even that out. Personally I would probably find a different image to use as a texture. The “planks” are so short that the wood grain features repeat too often. You could make a better photograph of a wood floor or find a better commercially available wood floor texture.