How does the government ban an os? Can't is a strong word, but I don't see that happening. It's a Canadian based foundation, not a Chinese or Russian company where they could argue national security in the same way they did with Huawei or TikTok.
It's more likely a federal os-level age verification law gets passed and grapheneOS compromises or backs out out of the US market.
By November 2026… after that who knows