There's nothing wrong with being on every platform. Although I would recommend using corporate platforms to steer people towards free ones. But they don't even seem to be on any of the free ones.

Telegram and Signal are just as centralised and vulnerable as Meta (to censorship, political blackmailing, metadata collection to incriminate its users, ...), just don't? Federated is much more resilient, and with Matrix being essentially an indiscriminate metadata aggregation and replication engine, prefer XMPP.