Can you mute the shutter sound for Japanese iPhones on iOS 15?

I don't know why this is still marked as the right answer when it isn't. I just bought my daughter a refurbished iPhone 7 and to our surprise the shutter sound could not be muted, so I started to investigate and realized we had been sold a Japanese model (A1779). Then I started to investigate whether there was any way to disable it and came across this post here, and was disheartened.

But after reading so many replies in this thread confirming that it could be done I just didn't understand how someone could be so sure it wasn't possible while so many others were confirming it was. However, I couldn't figure out why I wasn't able to mute the shutter sound on my daughter's phone. I updated to iOS 15.2 (it was on 15.1 when we got it) and still the shutter sound could not be muted. Then I came across a Reddit post indicating that you needed to be on iOS 15.x, be physically outside Japan and have a non-Japanese SIM card. Well, I met all three requirements and still could not disable the shutter sound.

So I decided to remove the SIM card and insert it again and... voilà. Now my daughter's Japanese model iPhone on iOS 15.2 can take photos silently!

So here is confirmation that it works, even on iOS 15.2 which just came out yesterday, so that maybe someone responsible for this thread can unmark the post I'm answering to as the correct answer and mark any of the many posts indicating that I can indeed be done as the right one.