Yup, Intel is struggling to enter the market, and they've been building similar chips for years. This just isn't an area for someone like Valve to break into.
Maybe they could make a good cooler design or something, but they're going to be using off the shelf chips, or maybe slightly altered custom chips like they did with the Steam Deck.
Yeah, but let's be real here, it would totally be just like Valve to make a GPU and somehow be like one of the best ones at the time and never make another one again.