> Can it be brutalist when you have the richness of wood in full display, veins, shimmer and knots all apparent?

Insofar as brutalism is about showcasing the raw building materials, yes, I think this is precisely what brutalism is about. Brutalism often uses concrete, but the big idea is to showcase the underlying material. (And if wood is more beautiful than concrete, great!)

IME, most people that complain about brutalism don't know what it is anyway and even if they roughly do, are only familiar with decades old ran down versions and not the original vision.