I envy you if you're only "a little bit worried"
The schedule gave us a week of hope.
I think Japan is playing fine except for a lack of scrappy floor defense. That's just not going to be there without Yuki and Risa. Reception is fine. I don't understand the default knee-jerk comments about Japan's reception being off. They must come from folks who aren't watching the matches. There are a few more "errors" than we'd like, but then the rest of it is pretty gosh darn excellent.
The service errors are a problem, too, in and of themselves, but they've also made them back off a bit so they aren't serving at the level they are capable of.
Japan can't "outscore" anyone, but if they score enough to stay in the game they can win by preventing other teams from scoring more. I don't even know what that means but I'm pretty sure it's correct Defense, baby!