>>71243483Niji Journey gets updates, but I don't think they're going out of their way to scrape Danbooru for more character tags. Midjourney heavily caters towards a “professional” (stupid middle-aged normie) audience, and VTuber fanart isn't a high priority for them.
I also just searched the Discord server for the most recent mention of Gura. This search includes the public image prompting channels.
The server has 19,349,603 members. The most recent Gura mention was 21 days ago, and it was... this.