I'd like to point out that thanks to Signal, WhatsApp has end-to-end encryption. So Zuckerberg likely wouldn't be able to snoop the content of that message.
Use Signal if you want a more trustworthy replacement, it's great! If you want something even better but less stable, check out simplex.chat.
if you're a cool tech wizard use xmpp
if you're a fever dream use Briar
if you're from the future.. is secushare nice?