So, a friend of mine spotted this today. Confirmed dust and water resistance of the Japanese X Compact from Docomo. Unsurprising, since international versions are also practically water resistant (mine's passed the pressure tests and someone on YouTube put it into a bowl of Pepsi), and the Japanese market is very fond of water resistance. By the way, they also have a new pink model, which doesn't look that bad although it's not my type. Here's the screenshot showing the pink model and water resistant certification. Link to the Docomo site is https://www.nttdocomo.co.jp/product/smart_phone/so02j/index.html if anyone's interested.
This is the video that you mentioned Docomo has to distinguish and promote its brand and assumes the risks, however, confined to only the country of Japan. Sony worldwide has received too many repairs warranty repair and can no longer afford the free care for so many smartphones I will not risk it anyway