Separate awarding of windows and shutters - GU resists!

Solid colored (granulate) a beautiful dream that has been dreamed again and again since the beginning of the plastic window era...

Why actually not? Duplo and Lego manage that too ;-)

Sun UV... damages the color and/or makes it unaffordable.

Doesn't Rehau have not only foil-wrapped but also fully dyed profiles ... or is that also acrylic?

All plastic window system providers (Rehau, ...) have colored profiles. Since the solid-colored PVC profiles ("base body") are not colorfast when exposed to outdoor weathering (sun, UV), a surface (lamination, co-extruded acrylic, ...) is always applied in some form that is colorfast.

If you can list the manufacturers of coextruded PVC windows, I would be happy.

Almost all plastic window system providers have coextruded profiles in some form. Only the plastic window system providers Gealan and, again since 2021, Kömmerling have coex with acrylic.