I can tell you just from anecdotal experience that changing my texture-arrays from 4k, to 2k, to 1k all have demonstrable performance differences in practice. Less-large the texture, less information is traveling around.
In my landscape/heightfield-mesh experiments, I have a decently expensive material. Changing around from 4k vs 1k it’s like a 12 fps difference for me at 4k resolution. And I know w.o specs that doesn’t really quantify it for you, but that it CAN be quantified, shows it’s valid…