Uncheck all "Use texture image" box to reduce the model size

I would like to reduce my model file, so it has many many components with textures in HQ, so if i pick that material, goes to Edit’s Material tab, and uncheck the “Use texture material” box, I realice that texture has gone and magically went replaced with a solid color, which is great because render softwares like lumion or twinmotion keeps recognizing each surface. And the model’s size went reduced dramatically. I would like to know if there is a way, maybe a plugin, to uncheck all “Use texture image” box of all materials of the model at once.

There are extensions that can reduce materials to a smaller amount of pixels, that might decrease enough filesize.
Checkout Material Resizer:

Make a copy of your file, first.
Set all materials to be 256 pixels (or lower) and then save the file to compare.