i can understand being dubious of WhatsApp given it's closed source and owned by Facebook. but Telegram and WeChat? Both closed source and with very questionable encryption? Signal is the only clear answer.
also side-note, WhatsApp audits and analyses have all come back confirming it's at least deploying the same end-to-end encryption as Signal, though stores a bit more metadata. so Facebook knows when / who you're messaging. Telegram / WeChat are much worse in this regard. as an anti western imperialist i'd still choose WhatsApp over Telegram / WeChat for comms. though ideally none of the above for anything important
this is cool as hell