Using ads will destroy the privacy and trust for sure. The ad networks will track anything and it all starts again.
I think users will need to pay a very small fee. That gives them control to be a legal owner of their account and data's. That is actually the argumentation of most other platforms to use and sell user data's, because they have no legal rights on their data's. By paying they have.
If you would offer an additional email address in a paid model, that would also secure the path from the platform to the user. Like 1$/month for Slyde. 2$/month Slyde with email address.
Second can be a an option to receive funds or donations. Third users and platform keep fake accounts under control when users need to pay something.
Also you should allow users optional to ID themselves by a third party service. That is very important for some public persons and many others. Later you can offer services between these users which bring you some extra income.