It is very interesting to see there's now an official Touhou news site by ZUN, I imagine that future games may be announced over there.
//Certain "Late-on",about my replybut not meant or out-of-turn //
The First and earlier announcements,preview,descriptions are through the social media-chat 'Yomoyama"(parent is Yokoyama Newshttps://x.com/Touhou_Yomoyama the same ,the bigger framed Link at the bottom -centre corner of the page Twitter / X linked account alike the ZUN (Jun'ya Ota),which is now mostly an archive and relay-link.
https://shanghai-alice.zendesk.com/hc/ja/requests/new/....More precisely for the Text-Form Question-to-Message,and"highlighting tools,snippets,characterization(Japanese and
International Adaption for non-ideogram Unicode-Westeern Language Packs )...mostly in Form Envelop-like,Legal,Multi-Combined Format the