Doh! Sorry. gave you the harder method...
Nah, that was correct one. Flat diffuse does it literally, which is not a good choice in most cases.
Blend channel on the other hand is actually very much neglected.
But it's powerful when it comes to animating texture or randomizing to some degree a tiled Base Color (like for grass fields).
Particularly when making masks in Multiply mode with sRGB selected.
(white color in Blend channel leaves Base Color texture intact).

Another method is to make animated base color texture (MP4). It can be made in most NLE from Base Color image using variable masks and effects.