OLED Decks were temporarily out of stock due to supply chain issues. Thankfully they’re now back in stock. Valve has also said they don’t expect supply chain issues/tariffs to affect Deck pricing, as part of their original statement about the shortage:
Steam Deck OLED 512GB and 1TB models are temporarily out-of-stock in the US and Canada as we adapt to recent supply chain constraints. We anticipate being back in stock by end of summer, and currently expect prices will remain the same. We’ll update here as soon as we have more clarity on what the timeline ultimately looks like.