There's no reason a private/paid service addon to a client can't work for filtering. Been thinking similarly for Mastadon, in that you can pretty easily have a gated experience, and get top ranking for Android/iOS client use with a monthly service that includes filtering with relatively sane defaults, but toggle-able filtering/reporting.

You can use fdroid, webapps or side-load the "full" unfiltered client but the experience for the normies would be that paid app experience. And I say paid app to avoid the pitfall that is advertising fed results.