Linear blending is called linear interpolation, it’s fairly straightforward. In your material, place two texture samplers and a local position node. The local position will give you the distance in centimeters on each axis from the pivot point of the mesh.
Use a componentmask to select the X, Y or Z axis from the localposition you want to blend along (R, G, B). You can divide that by the object radius to get something easier to work with, -1 to 1.
The lerp (linear interpolation) node’s alpha will blend 0 to 1, you need that instead of -1 to 1. Remap by adding 1 and dividing by 2 to the componentmask. Plug that into the Lerp’s alpha, and the samplers into A and B. Into basecolor or whatever you want and you are done.
you can adjust the blending width by multiplying the -1 to 1 step by whatever you want.