I think to figure out if it's a cultural difference or unwillingness for technological change, it'd be interesting to compare Korean or better yet Chinese apps, which were designed more recently.

In my brief experience,

- Promotional websites (e.g. https://ant.design/index-cn, https://seed.bytedance.com/zh/seedream4_0) seem to be designed similarly to Western websites

- Chinese mobile apps do seem to be more colorful in general (as observed with Japanese websites in the article), and some are more information dense, like Douyin Shop and Live. Bullet comments also add to the density

- I briefly worked at TikTok US, where the company uses Lark Suite. The desktop and mobile interfaces look pretty similar to Notion/Slack, but it has more vibrant colors and slightly more features (being an everything app for the workspace)