So it could be the case that Anita is the primary female protagonist in
Silent Hill f, and that this demo going by the title "
The Short Message" is something kind of like what Capcom did in 2016 for RE7, where you explored a house belonging to the Baker family, and the demo let you explore the rooms for the early part of the main game to create hype for their then new RE Engine. So this could be a part of that game, or perhaps a separate piece of canon, like how RE7 had all those 'lost tapes' to make up the DLC.
I'm only guessing, of course, but it does seem linked into
f, judging from having a similar looking monster present.
By the way, have a safe and happy start to 2023, you guys.