Nintendo Switch update 10.0.4 has been pushed out overnight. Since the download has just launched, you may need to set your console to update when you pick it up. I downloaded and installed the update myself today and can tell you that it only takes about one or two minutes at most, including the restart time for the console.
Nintendo Switch update 10.0.4 really only has one patch note. The issue that has been fixed was one that affected your ability to add funds to your Nintendo Account or add a new card in order to add funds or purchase games from the Nintendo eShop. More specifically: “We have fixed the issue where it was not possible in some countries or regions to add funds using a new credit card or to register credit card information in Nintendo eShop on Nintendo Switch.” It’s common for small updates like this to address just one little thing.
While most updates are downloaded automatically, I had to navigate to the System Update section of the Switch’s system menu in order to actually install it. If your Switch doesn’t automatically update, try doing the same and you should be able to get back to your games in mere seconds.