Tangential plug, I launched my own social network without feed, notifications, or even a way to find people there. It flopped everywhere I promoted it, but it is still online since I am on free tier of the host service. If anyone wants to check it: https://www.quidsentio.com
Have you considered lowering the barrier-of-entry from $19? For what is effectively a journaling app, you're driving an incredible amount of margin out of a scenario where your audience has no incentive to pay.