New to Matrix, looking for help with bringing friends over.

So I'll keep this brief. I really like Matrix's idea of a decentralized messaging platform, and after thr Telegram CEO got arrested in France, some friends are feeling iffy about staying there.

The main point of friction I'm encountering, however, is that whenever anyone goes and looks at Matrix and looks through available public servers to join, they're pretty quickly coming across some very undesirable rooms, to put it tactfully. Are there any ways that I could limit their visibility or ability to interact with those rooms? Server listing sites that make an effort to avoid listing those kinds of rooms, ways to block a room from showing up when you search within the client, etc? Currently we're running matrix.org accounts and using Element for PC/Android, to keep things simple.