An equally valid headline is "Investors purchased $8B of US Treasury Bonds". Never really got the point of people announcing US Treasury sales like its a big thing. Someone else not thinking with their emotions can, and will buy them. Its like announcing publicly you are selling your Honda. Its your Honda bro, sell it.
Sure, someone else is on the other side of the deal. But their demand is also satiated at a certain price point. Hell, if they wanted to buy from other sellers then it's not like T bills were not liquid.
Would you say the same if Norway's wealth fund offloaded their $181B? At those scales it would be more likely that it'd be visibly price affecting, and therefore affect the US's ability to borrow at existing cost.
So yes, when you sell your one NVDA, you are reducing demand and thus price. Epsilon, but nonzero.