user behavior – "Your application is empty!" / How to modify UI / UX to stop this kind of feedback?

I have an app to connect people around activities / outings.
There are two ways to suggest an activity / outing to other members:

  1. Invite everyone at once. All members could then see and participate in the suggestions.
  2. Attractive only some members, by selecting those of our choice (the members are listed in another tab and can be selected). Only these members would be able to see out and participate. Total confidentiality.

I have a real problem with UX.
To introduce the problem, here is a basic and light structure of my current user interface.

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Basically, two tabs, listing the actual (current or future) or past suggested outputs; and a list of the main content of the output.

Main comments from my users:
"The app looks empty, there aren't many suggested outings!"

The UI / UX clearly does not emphasize that "you, the users, are not supposed to see everything, you must see only the outings that concern you, that is to say to which you are invited! ".

I explain them briefly: "It's like emails, if I send an email to Julia, only Julia receives it, not you! So if you only see 3 displays displayed, it doesn't mean that another member can't see 3000 outs on their side. It all depends on whether they are invited or not. "

When I explain this, everyone LOVES the app and really starts inviting other members and suggesting themselves, without waiting. They become active and not passive.

How to transform my user interface so that the user understands the idea of ​​privacy / confidentiality of outs, and don't assume that "if I don't see a lot of outs in THEIR side, it means the app is" deserted "".

I thought of an interactive tutorial when I first launched the application.
I did it a few months ago, but I noticed that the majority of people have ignored it, thinking that it is a concept already known with other apps. and not innovative.
However, the privacy feature is quite innovative compared to other apps on the market and should really be noticed by users.
So, IMO, it's clearly a UX-issue application.