I'm not sure if there's any material limitation to it, but every PETG roll I've used has come out with a very glossy finish, which is probably not what you want here.
Matte PETG is available. No affiliation, but: https://californiafilament.com/collections/new . Great when you want the properties of PETG but not the shiny plastic look, e.g. printing things for car interiors. Like GP I'd also love to see this filament in PETG.
