Shared folders for me are an extremely rare use case (in fact, I generally don’t even use folders as I rely always on the search), but the way I achieve it is creating collections for the people to share it with. For example my “sister” collection in which I put stuff that I want to share with her, and give her access. Also each user can have their own collection that they can manage, to give access to other people (so far, this has never been the case for me).
MaggiWuerze