I just created a new forum (free-plan) and right after opening it, I had a notification about new features being available.
I remember notifications about upcoming changes being suppressed on new sites (FIX: Do not notify admins of upcoming changes on new sites · Pull Request #38890 · discourse/discourse). So, I thought maybe the same should happen for the “new features” notification. Just as a new admin doesn’t need to know about an upcoming change because they will start with their status right away, the admin also starts with all the features, so it doesn’t really matter which ones were added a few days ago compared to those a few weeks ago. As a new admin, everything is new.